· PREFA CE This manual is the third of a series of outlines for labora tory work in general...

COPYRIGHT, 1913

BY

HENRY HOLT AND COMPANY

T H E M A P L E . P R E S S . Y O R K - P A

PREFACE

This manual i s the thi rd of a series of outlines for laboratory work in general geology . Th e first i s a little manual

based on topographic maps of the United States Geologi calSurvey, designed for use in elementary coui

'

ses in physiography, and the second i s a similar manual for use in moreadvanced courses in physiographi c geology .

“

Th e presentoutline i s based on folios of the United States Geologi calSurvey

,and is intended to accompany courses in histori cal

and structural geology . Th e previously published manualsfollow the general order of Salisbury’s Physiography, an dChamberlin and Salisbury’s Geology, V ol . I, respectively .

Thi s manual may be used to good purpose with Chambe rlinand Salisbury’s Earth History

,Vols . II and III, but can

be adapted to any other thorough - going text on histori calgeology .

In presenting this manual to teachers, the authors believethat laboratory work

,such as here outlined

,has the same

importance for students of geology,that the more fami liar

phases of laboratory work have for students of chemi stryand physi cs

,and that no course in geology, involving such

topi cs as structural geo logy, the evo lution of the NorthAmeri can Continent

,or the geologi c history of the various

provinces of the United States,i s adequate W i thout an ao

companimen t of map work . They also believe that foliosof the United States Geologi cal Survey form the best basi sfor such Work . At the date of wri ting

,on e hundred and

iii

25801 2 .

0

w PREFACE

eighty- on e folios have been publi shed by the Survey, and

many of them,especially the more recent ones

,are well

adapted to the work outlined i n this manual . It i s alsoimportant that these folios should be understood and usedby persons other than students in schools

,for they are serv

iceable to miners,engineers

,contractors

,travellers

,etc .

,

when once understood by them.

Th e adaptation of these outlines to fit the needs,the time

,

the laboratory facilities,and the amount of laboratory

assistance available, must be left to the indi vidual teacher ;but two methods of presentation which have been used successfully by the authors, are suggested : (1 ) After theassignment of an exercise i s made

,the folios are placed where

the students may study them at their conveni ence . Th e

class is divided into sections of four, and an hour for con

ference with the instructor,subsequen t to the study of the folios,

i s named for each section . In these conferences,the topic of

the exercise i s di scussed informally, the folios being used fordemonstration . Either before or after conference, questionsso designated are answered in wri ting, and the papers givento the instructor for correction . (2) By the other method,d efinite laboratory periods are assigned, their duration andfrequency being determined by the time and general plan ofthe course

,an d the degree of preparation of the students .

In this case,all the work is done in the laboratory in the

presence of the instructor or hi s assistants . Th e studentswork individually or in pairs, and receive help or cri ti ci sm

from the instructor on demand . Th e second method is thebetter wi th younger students

,where time

,laboratory space,

assistance,and supply of folios are sufficien t .

Where the program i s flexible , i t i s better to have thelaboratory work timed to fit the class - room work, rather than

PREFACE

on specified days . Th e authors hold firmly to the viewthat

,apart from developing fami liarity with very useful

publi cations,the only functions of these laboratory exerci ses

in geology are (1) to i llustrate and emphasi ze the topics orprinciples discussed in the class- room,

or (2) to introduce newtopics or principles .For a group of twenty—five students in the laboratory

,

three or four copi es of each folio assigned are sufficient.

LABORATORY EXERCISES IN

STRUCTURAL AND

H ISTORICAL GEOLOGY

INTRODUCTION

Topographi c maps show the topographic forms resultingfrom the work of the various physiographi c agents , such asrunning water

,wind

,ground water

, glaciers, etc . From thestudy of these maps

,some interpretation of the various

processes involved in developing topography can be madewith confiden ce . Th e study of geologi c maps may carry thestudent further . Such maps show the various rock formations which appear at the surface

,and the structure sections

show their relations to each other,the positions of the beds

if the rock is stratified,the thicknesses of the formations , and

many other things to which attention is called in the exerciseswhich follow . From these various facts about the rocks of

a region,n ot only can the topography be interpreted more

certainly than from topographi c maps,but the history of the

region antedating the development of the present surfacecan be worked out . Th e principles involved and theirapplications

,are brought out in some detail in the exercises

which follow .

Though the adaptation of the exercises presented in thefo llowing pages must be left to the individual teacher, thequestions of each exercise are arranged for two somewhat

1

2 STRUCTURAL AND HISTORICAL GEOLOGY

distinct groups of students,the on e more advanced or pur

suing a fuller course,and the other less advanced or pur

suing a briefer course . To be more specific, students of thegrade of college seniors

, .

pursuing a course of about 120hours in histori cal geology

,after a thorough course in

physiography,would be regarded as belonging to the first

group ; while students of less maturi ty, pursuing a course of60 to 90 hours

,would belong to the second group . As

used by the authors,the complete ou tl ine of work presented

herewith accompanies a course which covers Vols . II an dIII of Chamberlin an d Sali sbury’s Geology . Omitting thequestions marked the work here outlined is done bysomewhat less mature students in connection with a halfyear course in histori cal geology

,based on the histori cal

part of Chamberlin an d Sali sbury’s College Geology .

Unless otherwise directed,studen ts of the first group

study all questions,an d answer in writing those marked

and Students in the more elementary or briefer coursesomi t the questions marked an d answer in writing thosemarked In many instances questions n ot marked forwritten answers lead up to those whi ch are to be answeredin writing ; hence a ll questions should be studied in order

,

and studied with care . Students who have some knowledge of geologic maps at the outset, may n ot need the simplerexercises of the Introductory Series . Ind ividual questionsmay seem to some teachers unnecessarily simple, an d theiranswers too obvious to need attention Number 1 ,under Exercise II) ; but the experience of the authors i sthat some such questions are needed by the averagestudent in the early stages of his work . There is, however,no obj ect in dwelling on questions or ideas which are well

understood .

STRUCTURAL AND HISTORICAL GEOLOGY

Th e work here outlined should include a minimum of

writing,but it should be done with great care . Th e written

answers should be concise an d to the point . Many of them

can be given in a word or a short sentence ; but in some cases,detai led explanations are called for . After hi s correctedpaper i s returned

,each student should revi ew the exercise

with the folios before him,i n order to see where mi stakes

were made .

While the deductions called for in the exerci ses are tobedrawn chiefly from the study of the folios

,reference should

be made to the text- book used in the course, whenever it wi llbe helpful .In the study of the folios

,most time should be put on the

Areal Geology or“Histori ca l Geology ” maps ; but

'

th e

Structure Section ” an d“ Ill ustration s ” sheets may be used

where they are found in the folios,an d the text of the folios

may be referred to,in order to corroborate conclusions .

“Surficial Geology ” sheets should be given especial attention in Exercise XIII .

By observing the location - in the United States of eachfolio studied

,a good idea of the geo logi c history of each prov

ince of the country can be obtained during the progress ofthe work .

Exercises I— VI should precede the stri ctly histori cal partof the course

,or accompany its very early stages . Th e

work outlined in Exercise VII should accompany,or fo llow

immediately, the class - room work on the Pre - Cambrian,and should be completed before work on the Cambrian i sbegun . Th e work outlined in Exe rc1se VIII should accom

pany, or follow immediately the study of the Cambrianperiod, an d be completed before the later Paleoz0 1c periodsare studied . Exercise IX might be divided into several ;

STRUCTURAL AND HISTORICAL GEOLOGY

but many of the principles involved were developed inconnection with Exercise VIII

,and the authors have found

that this Exercise (IX) may well stand as a un i t, an d ao

company the study of the later Paleozoi c Systems . Th e

assignment of this exercise i s made about the time theDevonian is completed, and i s finished before the Mesozoi ci s begun . Th e later exercises are used in a simi lar way .

It i s the authors’ experi ence that the earnest students set ahigh value on thi s work .

ALABAMA

GadsdenStevenson

- t ~

ARIZONABi sbeeB radshaw Mountains

CliftonGlobe

ARKANSASFayettevilleWinslow

COLORADOCALIFORNIA Elmoro

Bi dwell Bar Engineer MountainBig Trees Needle Mountains

1 The se folios may be ob tained from th e Dire ctor of th e UnitedState s Geological Survey, Washington, D . C . , for 25 cents percopy.

EQUIPMENT

Geologic Folios1

CALIFORNIAColfaxDownievilleLassen PeakMother LodeNevada Ci tyPyramid PeakReddingSan LuisSanta CruzSonora

?Truckee

STRUCTURAL AND HISTORICAL GEOLOGY 5

COLORADOOuray cot Bay

Rico RocklandSi lvertonSpanish PeaksTellurideTenmi le Distri ctWalsenburg

DELAWARE

Dover

DISTRICT OF

COLUMBIAMAS

Sfix

ISiESETTS

Washington

GEORGIA M ICHIGAN

Ringgold Ann Arbor

MenomineeIDAHO

Boi se MISSOURIJoplin

ILLINOIS

1221

53512 MONTANAFort BentonLi ttle Belt MountainsThree Forks

KENTUCKY NEW JERSBYEstillville F ranklin FurnaceLondon Passai cRichmond Trenton

MARYLANDAccident— Grantsvil l eChoptankNominiPatuxentPawpaw— Hancock

St . Marys


NEVV YORK

New York CityWatkins Glen— Catatonk

NORTH CAROLINAAshevilleCranberryMount MitchellPi sgah

NORTH DAKOTABi smarckCasselton— FargoJamestown— Tower

OKLAHOMACoalgateTahlequahTi shomingo

OREGONCoos BayPo rt OrfordRoseburg

PENNSYLVANIAAmityBeaverBrownsville— Connellsville

Burgettstown— Carnegie

PENNSYLVANIAClaysvilleElders RidgeElkland— TiogaFoxburg— ClarionGainesLatrobeMasontown- UniontownMercersburg— Chambersburg

PhiladelphiaSewi ckleyWarrenWaynesburg

SOUTH DAKOTAAberdeen— Redfie ldBelle FourcheEdgemontElk PointOelri chsOlivetParker

TENNESSEEBri cevi lleGreenevilleMayn ardvillePikevi lleRoan MountainSewanee


TEXASAustinEl PasoNuecesUvald

fi‘

VIRGINIABristolFrederi cksburgHarpers FerryMontereyNorfolkPo cahontasTazewell

WASHINGTONEllensburgSnoqualmieTacoma

WEST VIRGINIA

Buckhannon

CharlestonFranklinPi edmont

WISCONSINLancaster—MineralPoint

M i lwaukee

WYOM INGAbsarokaAladdinBald Mountain— Dayton

Cloud Peak— FortM cKinn ey

Devi ls TowerLarami e— ShermanNewcastleSundance

A . INTRODUCTORY SERIES

Before taking up the interpretation of geologi c maps,i t i s

necessary to have a clear idea of their make - up, and of themeaning of the conventional signs on them . Th e geologi cmaps publi shed by the U . S . Geo logical Survey are thestandard maps of this sort for the United States

,and the

folios of the Survey are the principal basis for the following studies . Th e purpose of Exercise I i s merely to in

troduce the beginner to geologi c maps .

EXERCISE I

GENERAL FEATURES OF GEOLOGIC FOLIOS

I. ASSIGNMENT

A . Two or three of the following folios

Cranberry, N C . Penobscot Bay, Me .

Engineer Mountain , Colo . Port Orford, Ore .

Mercersburg— Chambersburg,Pa . Roan Mountain

,Tenn .

Passai c,N . J Sewanee

,Tenn .

B. Chapters on Structural Geology in some standardtext- book, as Chamberlin an d Salisbury’s College Geology,

pp . 394— 413, or V ol . I, Geologi c Processes , pp . 486— 525 .

C . Description of Geologi c MapsPp . 2 and 3 of the cover of any fo lio of the U . S .

Geologi cal Survey .

Professional Paper 60, U . S . Geol . Surv ., pp . 12— 18,

8


II . OUTLINE FOR STUDY

1 . Note the following points in connection with the folios

assigneda) Th e number of maps, and the title of each .

b) What facts are shown on the Areal Geology Sheet

(any on e ) an d h ow are they shown ? A thorough understanding of this sheet i s necessary, as most of the work

'

of

thi s outline i s based upon simi lar maps . (Read carefully

pp . 2 and 3 of the cover of a recen t folio,and pp . 12— 18

of P rofession al Paperc) What is shown on the Structure Section Sheet

,in

add ition to what i s shown on the Areal Geology Sheet ?d ) Note the Illustration Sheet if the folio i n ' band

contains one .

e ) Make a brief outline of the topi cs considered in thedescriptive text . (Th e texts of the folios will be used in thi scourse chiefly to fin d data which cannot be read o from themaps di rectly

,or to corroborate conclusions drawn from the

study of the maps .)2. What three great classes of rocks are shown on geologi c

maps ? Have clearly in mind the origin of each class .3 . Defin e system

,series

,formation

, as applied to rockdivi sions

,and era

,period

,and epoch

,as applied to the

divi sions of geologic time .

4 . Note the meanings of the various colors on the Area]Geology Sheet .5. On the Areal Geology Sheet

,note carefully the con

ven tion s (symbols) for stratified rocks ; for igneous rocks ;for metamorphi c rocks ; and for surface formations

,such

as glacial drift,alluvium

,etc .

6. Noti ce that th e Areal GeologySheet shows topography,


as well as the areas where the various rock formations come

to the surface .

7. How are faults shown on geologi c maps ?

8. Draw diagrams showing at least two types of

uncon formity .

9 . Li st the geologi cal events recorded by the diagrams in 8.

10 . a) Study the legend on the Areal Geology Sheetcarefully .

b) Note the chrono logical order of the di fferentformations, as given in the legend (oldest at bottom of

column) .

1 1 . Explain what i s meant by dip an d strike . How arethey shown on the Areal Geology Sheet ?

EXERCISE II

FOLIOS SHOWING HORIZONTAL OR NEARLYHORIZONTAL SEDIMENTARY BEDS

I. FOLIOS TO BE STUDIEDAmi ty

,Pa . Lancaster-M n eral Point, Wis .

Buckhannon, W. V a . Sewanee,Tenn .

Charleston,W . V a . Washington , D . C .

Coalgate, Oh . (I . T Waynesburg

,Pa .

Elkland— Tioga,Pa .

II . OUTLINE FOR STUDYN 0 te .

— Students in more elementary an d bri efer coursesomi t questions marked and answer in writing questionsmarked

Students in more advanced courses study all questions,

and answer in wri ting those marked and

A . Gen eral Question s

*1 . Draw a diagram showmg how the relative ages of bedscan be tol d by their positions with reference to on e another .2 . If perfectly hori zontal strata underlie a perfectly flat

surface, how many formations will outcrop ?*3 . a) Given a flat surface underlain by horizontal strata,each stratum 50 feet thi ck

,i n which there are valleys not

more than 25 feet deep ; h ow many strata will outcrop ?b) Given the same conditions as i n a) except that the

1 1.

https://www.forgottenbooks.com/join


4 . In what ways may the varying thickness of Nc be

interpreted

5. What inference may be made from the distribution of

N1?*6 . How may the fai lure of Kp to underli e N1 i n some

places,as at Wesley Heights (245 mi les northwest of Wash

ington ) be explained ?At what times was the region subjected to subaerial

erosion, as shown by the relations of the formations ?

Sewan ee Folio

1 . Note the di stribution of outcrops .2. Note the position of the beds .Determine from the Areal Geology Sheet the thi ckness

of formations Cw and Cl, at a point six mi les north - northwest of Jasper

,i n the southeastern part of the area .

Explain the areas of Cw surrounded by C1. Gi ve all”

conceivable explanations . Which is correct ?

Charleston Folio

From the Histori cal Geology Sheet,determine (1 ) the

di rection of dip,an d (2) as nearly as possible its amount .

Buckhann on Folio

*1 . Explain the arrangement of outcrops along the bottomof the valley of Buckhannon River .

Coalgate Folio:*1 . Determine the stratigraphi c relations of formation Nga l*2. The cause of the belted arrangement of the Carbonif

erous formations in the northern half of the area ?Account for the varying width of the outcrops of some

of these formations,notably Ct .


E lkland Ttoga Folio (Ttoga Sheet)Study the di stribution of outcrops east of Tioga

,i n

relation to the distribution of contour lines . Th e i nference ?Test your conclusion by reference to the Structure SectionSheet .

Wayn esburg Folio

* 1 . Noti ce the dendriti c shapes of the outcrops . Th e

i nference*2. Determine the elevation of the top of formation Cw at

several points along the parallel of 39° and along themeridian of 80

° What inference from the above ?3 . Determine the thickness of formation Cw in the extreme

northeast corner of the central rectangle .

1

Amity Folio

1 . Note the distribution an d shapes of the outcrops .2.

**a) Explain the outcrop of formation Cm surroundedby Cw (eastern part of central rectangle) .

>l‘b) Explain outcrops of Cg surrounded by Cw i nsoutheast part of central rectangle .

*3 . What are the stratigraphic relations of Q cm ?

In what direction do the strata dip ?Determine

,at least roughly, the amount of dip .

Lancaster -M tn em l Poin t Folio

l . Note the dendriti c character of the outcrops .2. Study the Areal Geology Sheet for thi ckness an d

s tructure of beds .

Th e name re ctangle is applied to the smalle st area bounded byparallels and meridians on a map .

EXERCISE III

FOLIOS SHOWING DEFORMATION OF SEDIMENTARY BEDS WITHOUT FAULTING

i. FOLIOS TO BE STUDIEDAccident— Grantsvi lle

,Md . Lancaster— Mineral Point,

Bristol,V a . Wis .

Coalgate,I . T . (Ok . ) Newcastle , Wyo .

Franklin , W . V a .

H . OUTLINE FOR STUDY

See N ote, p . 1 1 .

1 . Compare the Areal Geology Sheet of the LancasterMineral Poin t fo lio with the corresponding maps of the restof the folio s of the li st assigned . Explain why most of theoutcrops shown on the former have a dendriti c arrangement

,

while the formations shown on the other maps outcrop inbelts .

N ewcastle FClio

1 . Study the cases of simple, but pronounced deformationshown by the structure sections .

2. Note the type of deformatl on shown by the structuresections .

Bristol Folio*1 . Explain the belted arrangement of the outcrops .

*2. How much may be inferred from the topographi cmap concerning (1) the kinds of rock which underlie theregion

,and (2) thei r structure ?

15


*3 . From the Histori cal Geology Sheet,determine the

position of the beds between Corn sville (center of westcentral rectangle) and Early Grove (northwest part of southcentral rectangle) .

Account for the looped outcrop of Cn i n the northwestrectangle .

Th e structure of the beds in the basin of BrumleyCreek, northeast rectangle .

*6 . State a law for determining the direction of dip of stratafrom geologi c maps .*7 . How may anti clines be di stingui shed from synclines ongeologi c maps ?*8 . Given a formation with a dip of outcropping on aflat surface

a) Increase the dip to does the outcrop increaseor decrease in width ?

b) Decrease the dip to 1° does the outcrop increase or

decrease in ”widthc) If the dip becomes what relation is there

between the width of the outcrop an d the thickness of theformation*9 . Given a hori zontal formation outcropping on a hillsidewhich has a slope of 20°

a) Decrease the slope of the hill to does the outcropincrease or decrease in width ?

b) Increase the slope of the hill to does the outcropincrease or decrease in width ?

0 ) Increase the slope of the hill to what relation i sthere between the width of the outcrop and the thi cknessof the formation ?

Formulate a law which will express the relation be

tween slope of surface, dip of strata,and width of outcrop

,


Coalgate Folio

*1 . Explain the belted arrangement of the outcrops of theseveral formations .*2 . In what di rection do the strata in the north part of thearea dip ?*3 . Why are the outcrops of Ct

,Cst

,Csn , etc . ,

broader inthe northeast than in the west central part of the distri ct ?Test your conclusion by reference to the S tructure S ectionSheet .*4 . Account for the area of Cm within Cs

,east central

part of map .

Determine from the Histori cal Geo logy Sheet thestructure of the beds northwest of North Boggy Creek

(southeast part of map) , along the line BB. Test youron clus1on by reference to the Structure Section Sheet .

Why does the outcrop of Cm disappear to the northeast of Cottonwood ? If the surface rose i n that direction

,

would there be an alternative explanation ?Why is the Cb area southeast of Coalgate not con

n ected with the Cb area to the northeast ?Show by diagrams h ow a belted arrangement of

outcrops may appear on a hillsi de, without a tilting of thebeds .

Franklin Folio

1 . What inference as to structure may be made from thetopographi c map ?

2. Th e character of Stc,as suggested by the structure

sections*3 . From the details of the eastern slope of the anticlinal mountain shown in section AA

,Structure Section


Sheet, what inference may be made con ce rning the relativehardness of the beds ?4 . Study the structure sections for the relation between

the degree of folding and the amount of erosion .

>l‘5. a) How may the looped arrangement of the Son and

Sr outcrops near Elkhorn Rock be interpreted (northeastpart of Areal Geo logy Sheet)

b) What does the appearance of Sen an d Sr eastof M i ll Gap mean ? (Th e topographi c map wi l l be of as

sistan ce i n answering this question . )How are the small areas of 81 j ust west of the South

Fork of the Potomac River in the northeast rectangle,to be

interpreted

Interpret the loop - shaped outcrops of Sr northwestof Franklin .

*8. Interpret the i rregular contact between the Devonianand Carboniferous outcrops in the northwest part of themap .

>l‘9 . Account for the i solated outcrop of Cpo, i n Dh , directly west of Onego (N. W. rectangle) .

Account for the various outcrops along the line of

Reed Creek (western part of central rectangle) .Th e date of the fold ing of the beds of this area ?Show by a series of drawings the effects of various

topographi c forms upon the shapes of outcrops .

Acciden t— Gmn tsville Folio

1 . Study the strip of Cpo extending in a northeastsouthwest direction across the center of the Grantsvi lle

sheet:*a) Is the formation dipping or horizontal ?

b) What of the amount of dip ?


**c) Determine the direction of dip by the shape of the

outcrop at stream crossings,without reference to the age of

the formation s .Determine the structure of Dj (Gran tsville Sheet) by

the relation s between streams an d the shapes of the out

crops on either side .


>14 . a) After faulting, will the upthrow or the downthrow

side suffer more erosion ?

b) How can the upthrow side be distinguished from

the downthrow side on a geologi c map ?

5. Define the terms strike ,dip ,

and oblique- faults .

Show by diagram how the outcrop of a dipping bed

i s shifted by erosion .

7 . If dipping beds are faulted,an d the upthrow side i s

eroded more than the downthrow side, the outcrop of thedipping beds will be shifted farther in the di rection of dip on

the upthrow side,than on the downthrow side .

**Illustrate this point by diagram or simple maps,i n

the case of both dip and oblique faults .Draw a simple sketch map showing offsetwith overlap .

Designate the upthrow side .

Show by diagrams how outcrops may be cut out,dupli cated

,narrowed

,and broadened

,as a result of strike

faults .10 . Do reversed faults occur more commonly with hori

zontal or with dipping beds ? Explain .

B. Question s on Faltos

Brieem’

lle Folio1 . Are the strata hori zontal or folded in the southeast

part of the area ? In the west an d northwest parts ?*2. Locate faults on

‘

the Areal Geology Sheet .3 . Are most of the faults strike

,dip or oblique faults ?

*4 . Are the faults normal or reversed,as shown in the

structure sections ?From what directions were the forces probably

applied which resulted in the folding and faulting of the

region ?


Determine as nearly as possible the date of thefaulting .

Pocahon tas Folio*1 . From the Areal Sheet

,work out i n as much detai l as

possible the structure at Burke Garden, in the southwestern part of the map .

What is the structure at Round Mountain (north - eastern part of south central rectangle)

What i s the structure at Nye Cove,in the south

western part of the central rectangle ?Account for the sequen ce of outcrops along the val

ley of Roan ng Fork, southwest of Burke Garden .

What is the direction of dip of the formation Cpc,northwest of Sharon Springs

,south centra l rectangle ?

*6 . Account for the j uxtaposition of Cpc an d 6 83 inthe southeastern part of the map .

7 . Account for the protrusion of Devonian into Car

bonife rous 5 mi les northeast of Effna in the south centralrectangle .

Explain the peculiar break in ’ the outcrops of Sr andSDg, southeast of Effna .

9 . How may the crenate outline of many of the outcropsbe explained ?

Tahlequah Folio

1 . What i s the general structure of the formations ?Explai n the fai lure of the Devonian beds to o ccur

between Ssc and Cbn i n the small valley .2 mi les north of

Bunch in the south central part of the central rectangle .

3 . Explai n he outcrop of O t in the valley of BarrenFork (north central part of map) .

Explain the i solated outcrops of Gwl and older Car


boniferous beds i n the central and north central parts of

the region .

*5 . Determi ne the downthrow side of the several faults in

the western part of the area .

Explain the small outcrop of Do i n the center of thenortheast rectangle . Note the topographi c expression

of Dc .

*7 . a) Which is the downthrow side of the fault cuttingthe small hill five mi les due northeast of Wauhillan (north

central rectangle)b) Same for the fault cutting Ch l seven mi les southeast

of Wauhillan .

Are the faults of thi s distri ct probably normal or

reversed ? Why ?

Engin eer. Moun tain Folio

Study the faulted area in the east central part of thenortheast rectangle

,as fol lows :

a) Determine the upthrow side of each of the two faultscutting De .

b) Having determined the upthrow sides of the faults,in what di rection does De dip ?

0 ) How many periods of faulting have there been ?Give dates .

(1) Explain the disappearance of De and DCo to

the north .

2 . Determine the upthrow sides of the two faults in thesoutheastern part of the central rectangle .

Mercersburg— Chambersburg Folio

*1 . Which i s the downthrow side of the fault in thenorthwestern part of the central rectangl e, and the south


eastern part of the north central rectangle, Chambersburg

Areal Geology Sheet ?

2 . What i s the direction of dip of Cc and Osh ?Follow the outcrop Oc along the strike from St .

Thomas (southern part of northeast rectangle, MercersburgSheet) to the south edge of the map . Explain in detail alldi scontinui ties .

Explain the outcrop of Q C on e mi le southwest of

St . Thomas .Th e fault line shown in the southwestern part of the

Mercersburg sheet,running between Cove Mountain an d

Little Cove Creek, i s i n contact with several different formations in its course . Explain .

Determine the amount of throw of the fault betweenS cy and Do (S . W . part of Mercersburg Sheet) , as nearly

as possible .

Work out the sequence of faulting south of

M ercersburg .

Roan Moun tain Folio

1 . Noti ce the. peculiar courses of the faults arou’

nd

Cherokee and Buffalo Mountains (west central rectangle) ;

give possible explanations .

2. See structure'

sections and text for correct explanation of 1 .

EXERCISE V

FOLIOS SHOWING VARIOUS PHASES OFVULCANISM

I. FOLIOS TO BE STUDIEDElmoro

,Colo . Spanish Peaks

,Co lo .

Fort Benton,Mont . Sundance

,Wyo .

Passai c,N J Walsenburg, Colo .

Port Orford, Ore .

II. OUTLINE FOR STUDYSee N ote

, p . 1 1 .

A . General Question s

1 . What are the more common igneous rocks named i nthe legends of these folios ?

2. What is the origin of igneous rocks ?

3 . Name three groups of igneous rocks, classified according to the si ze of crystals .

*4 . From the legends of the folios,choose formations in

which the rocks have resulted from the cooli ng of intrudedlava ; of extruded lava . (Have in mind the relation betweenthe rate of cooling and the Sl ze of the crystals ; also the relation between the rate of cooling of extruded and intrudedlavas . )

5 . Eicplain how intrusive igneous rocks may come to beat the surface .

*6 . Draw a diagram or a seri es of diagrams showing the25


various forms assumed by ign eous rocks,both intrusive an d

extrusive . Apply the proper geologi c name to each of theseforms .

How may the age of igneous rocks be determined , i fthey are associated with stratified rocks of known age ?Does the law of super- position always apply in thi s conn ection ? Does i t ever apply ? Explain .

B. Question on Folios

E lmoro Folio

1 . What is the age of the igneous rock ? Test the conclusions reached from the study of the Histori cal GeologySheet

,by reference to the Structure Section Sheet

,and

finally to the legend .

2 . What evidence i s there of erosion since the outflow

of th e lava ?

3 . Has the lava accelerated or retarded erosion ? Rea

sons for answer .4 . What inference can be made as to the origin of the

lake basins on the top of the Raton Mesa ?

Walsenburg F01730

1 . Study carefully the series of dikes shown on the Ign eous Geology Sheet southwest of Rouse

,i n the southern

part of the map . Compare with the Topographi c Sheet .*2 . Explain the looped outcrops of llp, elp, and bs (southcentral rectangle) .

Which is older,elp or llp, central part of central

rectangle ?*4 . Note the dike in the extreme south central part of

the map . Which took place first, the faulting or the in

trusion of the dike ?


If the east side of the fault mentioned under d ) i s thedownthrow side

,whi ch way does the dike dip ?

What was the date of extrusion of smp relative to thefaulting

,and to Nn (west central part of map) ?

What are the relative ages of bs an d Nn in the extremewest central part of the area .

Span ish P eaks Folio

1 . Determi ne from the Histori cal Geology and StructureSection sheets the dates of the vol cani c activi ty .

2 . How do the many dikes of the area affect thetopography ?

Might the present surface relations of the Cretaceous an d Eo cene beds east of the mountains hold

, ( 1) i fthe beds were horizontal ? (2) If they dipped to the west ?

(3) If they dipped to the east ?How has the intrusion of ad affected Eh in the south

west part of the northwest rectangle ? (See Structure Section Sheet and legend . )

P ort Orford Folio

1 . Note the kinds of intrusive rocks .>l‘2. Determine from the Areal and Structure Sectionsheets the age of the igneous rocks .

"

How many times and when were the sedimentarybeds of the area deformed ?

What hypotheses may be advanced to account for thethe isolated patches of sedimentary rocks within igneousrock areas, shown on the Areal Geology Sheet ? Test yourtheori es by reference to the structure sections .

FortBen ton Folio

1 . Study the maps of this folio for examples of laccoliths and bysmaliths .

EXERCISE V I

FOLIOS SHOWING METAMORPHIC ROCKS

I. FOLIOS TO BE STUDIEDBradshaw Mountains , Ari z . Penobscot Bay, Me .

Co lfax, Cal . Pyramid Peak, Cal .

Cranberry, N C . Spani sh Peaks,Colo .

See N ote, p . 1 1 .

The processes of metamorphism should be well i n mindbefore the study of the folios i s undertaken .

A .

“

Gen era l Question s

*1 . What i s the relation be tween metamorph i c rocks andsuch diastrophi c forces as those which produce folds andfaults ?*2 . What relation is there between vulcanism and metamorphism ? See the Eh and Em formations around WestSpanish Peak (Spanish Peaks folio) .*3 . What sequence of events i s recorded by a metamorphi cformation, such as mi ca schist, underlying a sedimentaryformation which has not been metamorphosed ?

B. Question s on FoliosColfax Folio

1 Note the various kinds of metamorphi c rocks shown .

*2 . From the metamorph i c rocks of the legend, d esig29


nate on e formation which is meta - sedimentary,and on e

which is meta - igneous .*3 . What can be said of the relative ages of sp and am ?

Refer to the Histori cal Geology Sheet and the StructureSection Sheet .

What are the relative ages of sp and pr (northernpart of south central rectangle) ?

From the Structure Section Sheet,determine the date

or dates of deformation of the beds .At what time or times were the rocks metamor

phose d ?

7 . What is the meaning of the small patches of Najust north of the Ameri can River (central and east centralrectangles) ?

Pyramid Peak Folio

1 . Note the various kinds of metamorphi c rocks inthi s area .

Th e date or dates of deformation of the beds ?Th e probable time or times of metamorphism ?

4 . Is there evidence of the former greater extent of theigneous formations ?

Cranberry, Bradshaw Mou’

n tains , and P en obscot Bay

Folios

1 . In each of these folios, study the various meta

morphi c rocks shown, their relations to each other, and thei r

relations to the igneous rocks .From the facts worked out in a) , determine the dates

of metamorphism i n each of these regions .


B. SYSTEMIC SERIES

Having become fami liar i n the preced ing exerci ses withgeologi c folios, an d with some of the principles invo lved intheir interpretation

,and having learned to read something

of geologic history from the rock record as shown on thefolios

,we turn to a study of the various systems of the

geologi c column in North Ameri ca . These systems wi ll beconsidered in chronological order . Th e study of the following exercises wi ll result in (1 ) greater efficie n cy i n theinterpretation of geologi c maps

, (2) greater fami liari ty withthe principles invo lved in the development of the manystructural features shown by the maps

, (3) a better workingknowledge of the methods employed in reading the historyof the earth from t h e record of the rocks

, (4) an introductionto the history of the various regions of the United States inthe di fferent eras an d periods of geologi c time

,an d (5) some

degree of fami liari ty with the general history of the earth .

These exercises should emphasize the principles and factsdeveloped in the class - room .

EXERCISE V II

ARCHEOZO IC AND PROTEROZOIC (ALGONKIAN)

I. FOLIOS TO BE STUDIEDAshevi lle, N C . Mercersburg— Chambersburg,Bald Mountain— Dayton, Wyo . Pa .

Bi sbee, Ari z . Needle Mountains, Colo .

Cloud Peak— Fort M cKinn ey, Ouray, Colo .

Wyo . Parker, S . D .

Cranberry, N C . Passai c,N J

El Paso,Tex. Patuxent

,Md .

Frankli n Furnace,N J Penobscot Bay, Me .

Globe,Ari z . Ri co

, Colo .

Harpers Ferry, V a . Sundance

,Wyo .

Holyoke, Mass . Ti shomingo,Ok .

Menominee,Mich . Washington

,D . C .

II . DIRECTIONSIn answering the questions below,

most,i f n ot all

,of the

above folios should be studied . If the questions cannot beanswered sati sfactorily from the geologi c maps alone, thetext of the folios should be stud ied . Note at the outset inwhich geologi c province of the United States the area of

each folio li es .See N ote, p . 1 1 .

STRUCTURAL AND HISTORICAL GEOLOGY 33"

m . QUESTIONS

1 . Outline the general distribution of the Archean andProterozoi c (Algonkian) as shown by the folios .

2. Note the kinds of rocks (see legends) in the Archean

an d Proterozoi c (Algonkian) i n each region .

3 . Explain the forms of the outcrops, such as narrowbelts

,broad areas

,etc .

4 . Note the topograph i c positions of the outcrops .*5 . Make a comparative study of the structures andstructural relations of the Archean an d Proterozoi c i n thefollowing regions

,and illustrate wi th diagrams the different

relationships showna) New England (Holyoke an d Penobscot Bay folios) .b) Pi edmont Plateau (Patuxent andWashington folios)c) Appalachian Moun tains (North Carolina fo lios) .

d ) Th e Southern Interior (El Paso and Ti shomingofolios) .

e ) Th e Northern Great Plains (Parker an d Sundancefolios) .

f) Th e San Juan Mountains (Co lorado folios) .

g) Th e Bighorn Mountains (Bald Mountain— Daytonand Cloud Peak— Fort M cKinn ey folios) .

h ) Th e Ari zona Region (Globe and Bi sbee folios) .

>I<6 . State briefly, but comprehensively, the geologi chi story recorded in each relation ship shown by the aboveseries of diagrams .

State, i f you can, whether or n ot the pre - Cambrian

rocks were ever covered by later deposits in each of theregions given in 5 .

8. How has vulcanism affected the pre - Cambrian rocksi n the different regions ? Fix the date of vulcani sm as

closely as possible in each case .

3


9 . Th e metamorphic rocksa) Date of metamorphism

,i f determinable ?

b) Mode of metamorphism ?c) Th e antecedents of the metamorphi c rocks ?Work out the physi cal history of the Menomi nee

region .

EXERCISE V III

CAMBRIAN

I. FOLIOS TO BE STUDIED

A . Folios for E lemen tary and Briefer Courses

Absaroka;Wyo . Gadsden, Ala .

Bald Mountain— Dayton,Harpers Ferry, V a .

Wyo . Morri stown,Tenn .

Bristol,V a . Philadelphia, Pa .

Clifton, Ari z . Tazewell,V a .

Frankli n Furnace,N. J. Ti shomingo, Ok . (I . T. )

B. Additional Folios for M ore Advanced Courses

Asheville,N C . M ercersburg— Chambers

Rl Paso,Texas . burg

,Pa .

Estillville,Ky. Needle M ountains, Colo .

Fort Benton, Mont . Pi sgah,N C .

Greeneville, -Tenn . Ri co, Colo .

Holyoke,Mass . Ringgold

, Ga .

Maynardville,Tenn . Rockland, Me .

Menominee,Mich . Three Forks

,Mont .

Tinti c, Utah .

II . DIRECTIONSE lemen tary Classes .

-Study only the fo li os of group A .

Study all questions,except those

‘

marked and answer inwriting those markedAdvanced Classes .

—Study all the folios of groups A and35


Narcissa,south to the final “

1”

of Spring Mill,extreme

east central part of Norristown Sheet .b) Name the structural feature shown on the above

section .

c) Outline the physi cal history as shown in the abovestructure section .

Gadsden Folio

1 . Th e position of the beds ?With what systems do the Cambrian outcrops come i n

contact ? Explain these contacts .

Tazewell Folio

1 . Th e topographic position of the outcrops ?

2. Work out the structure along the lin es of the section s

(AA,BB

,etc . ) from the Areal Geology Sheet, then compare

with the structure sections .

>l‘3 . Make a northwest - southeast structure section starting

two and on e - half mi les north of the southwest corner of themap .

Bristol Folio

1 . Make a detailed study of the outcrops in the southeastpart of the map .

>l‘2. Make a structure section from Bristol,three mi les

to the northeast .Make a northwest- southeast structure section through

Bristol and Tabor,from Papervi lle on the southeast

,to the

Carboniferous on the northwest .4 . Work out in detai l the history of the faulted area 25»

mi les northeast of Lebanon; in the northeast rectangle .

Work out, with diagrams, the history which has resultedin the structure shown at the contact of Carboniferous a nd


Si luri an west- northwest of Bristol, i n the third structuresection .

M orristown Folio

1 . Note the general di stribution and arrangement ofCambrian outcrops .2. Note the widths of outcrops and thei r variations .3 . With what other systems do the Cambrian outcropscome in contact ?4 . Study the succession of Cambrian outcrops along the

lines of the sections as indicated on the Areal Geology Sheet,

and interpret . After the in trepretation i s made,study the

Structure Section Sheet .

5. What i s the meaning of the shape of the northeasttermini of the Cambrian outcrops near Morristown ?

a) What possible interpretations ?b) Which interpretation is right ?

What is the structure determining the Cambrian out

crops northwest of Flat Gap near the southwest corner ofthe sheet ?*7. M eaning of the Cambrian extension

‘

(6 11) northeast ofthe town of Flat Gap, in the southwest rectangle ?

Meaning of the form of the Crg outcrop from TateSprings (northwest of the center of the map) to i ts terminus,6 miles or so farther east ? Meaning of the abrupt terminus ?*9 . Interpret the enclosed Crg outcrop at Mooresburg.

(Note the form of the outcrop where crossed by the smallstreams . )

M eaning of the Crg outcrops to the northwest of thelast

,incl uding the on e farthest northwest i n this group ?

*1 1 . Meaning of the Sk belt in Cu ,4 mi les and more

south- southwest of Morristown ?


*12. Meaning of the eastward extension of the Cmoutcropthree mi les west- northwest of Turley Mills (center of west

central rectangle)*13 . What possible interpretations may be placed upon an

outcrop which varies i n width from point to point ? Makediagrams to i llustrate .

14 . What i s the meaning of abrupt ends of outcrops likethat of Cn j ust southwest of Nocton (west central rectangle)

Possible meanings of 6 11 outcrops near southeastcorner of the sheet ?16 . Meaning of the great expansion in width of Crs in the

northwest part of the map ?

*17 . Make a northwest - southeast structure section throughNoe ton across the belts of Cambrian on either side .

Make a simi lar section through Turley Mills .Near the northeast corner of the southwest rectangle

,

a fault line lies for a distance between Sk and Crt ; tracednortheast, i t li es between Cm and Cn . Interpret .

Note the Crs outcrops north and west of Tate Springsnote its termini in both directions . Note also i ts relation toother formations

,and interpret .

In general , how i s a strike fault whi ch crosses formations to be interpreted ?22 . Note the outcrop of Crs 1 7} mi les southwest of

Mooresburg, and i ts relations . What is the explanation of

i ts presence ?23 . Explain the variations in the width of Crg near Cobb

Ford in the northeast part of the central rectangle .

H arpers Ferry Folio

1 . With what systems do the Cambrian outcrops come incontact ?


How were these contacts brought about ?

3 . What evi den ce is there that the Cambrian rocks wereonce more widespread than n ow ?

Greeneville FolioExplain fully the sequence of outcrops along the north

east - southwest fault line j ust east of Greeneville, in the northwest corner of the south central rectangle .

2. Explain the looped outcrop of Cu southeast of LocustSpring in the northwest corner of the central rectangle .

2 . The In terior Region

Tishomingo Folio>t l . Th e meaning of the form of the area of Cr, east of

Sylvan,i n the west central part of the map ?

2 . With what systems does the Cambrian come in contact ?

Th e explanation of the diverse juxtaposition s ?

3 . Western Moun tain Region

Bald Moun tain — D ayton Folio1 . What are the indications that the Cambrian once had

a more extensive distribution than n ow ?

*2 . Why does Cd outcrop more extensively in the Bald

M ountain quadrangle than in the Dayton quadrangle ?

Explain the looping of Cd to the east, where crossed by

Tongue River (northeast part of west central rectangle,Dayton Sheet) .

Give a detai led explanation of’

the outcrop and the

form of the outcrop of Cd , in the northeast part of the Bald

Mountain quadrangle ,


*5. What is the structure of Cd at Porcupine Canyon , inthe west central part of the northwest rectangle (Bald

Mountain Sheet)6 . What are the stratigraphi c relations of the Cambrian

to the Ordovi cian ?In the fie ld

,where would you look for the continuation

of Cd , after its interruption in the southeast part of the

Dayton Sheet ?

Absaroka Folio (Crandall Sheet)

1 . Note the position of the beds.

*2. What is the significan ce of the di stribution of Cambrianoutcrops

3 . What is the structure which gives ri se to the arrangement of outcrops in valleys crossing the Cambrian ?

Why do n ot the Devonian and Carboni ferous stratashow on the lower part of the canyon wall s down stream ?

Tin tic Folio

1 . Study the structure sections,and pp . 4 and 5 of the text

of the folio .

Clifton Folio

1 . With what systems of rocks i s the Cambrian associated ,an d what are i ts relations with each ?

What i s the explanation of the scattered outcrops of

Cc in the central and west central rectangles ?*3 . Which i s the downthrow side of the fault cutting Cc,

on e mi le north of Coronado M t,i n the central rectangle ?

Are there two faults or three 1} mi les south of EnebroMountain (north central rectangle) ? If two

,i s the earlier

one a reversed or a normal fault ? Explain ,


4 . Gen era l Question s

*1 . What i s the areal distribution of the outcrops of thesystem as shown by the folios ?*2. State the general character of the rocks of the systemi n the various regions

,such as the Appalachian region, the

interior,the western mountains

,etc .

,where they outcrop .

What is the position (general structure) and what thecondition of the Cambrian strata and of associated igneousrocks (ii any) i n the severa l regions of outcrop ?*5. Which type of faulting is dominant in the Tennessee

regionWhat are the economi c resources of the Cambrian

formations , so far as ind i cated by the folios ?Be on the lookout for special points not included in the

above general questions . Make a list of such points .

In addition to th e folios listed in th e exercise above , thosenamed be low also show outcrops of th e Cambrian sy stem . Inlocalitie s where th e Cambrian system occurs, local folios, wherethey exist, may be substituted for some of those listed in th eexercise , or added to them .

Anthracite - Cre sted Butte , Colo .

Cle ve land, Tenn .

Cloud Peak— Fort McKinn ey , Wyo .

Cranberry, N C.

Engineer Mountain, Colo .

Hawley, Mass .Kingston, Tenn .

Knoxville , Tenn .

Little Be lt Mountains, Mont .Livingston, Mont .Loudon, Tenn .

Mine La Motte , MQ.

Mount Mitche ll, N C.

Nantahala, N. C.

Penobscot Bay , Me .

Pikeville , Tenn .

Pawpaw— Hancock, Md .

Rome , Ga .

Silverton, Colo .

Staun ton, V a .

Sundance , Wyo .

Tenmile Distri ct, Colo .

Trenton, N J

Yellowstone, Wyo .

EXERCISE IX

ORDOVICIAN AND LATER PALEOZOIC

SYSTEMS

I. FOLIOS TO BE STUDIEDA . Folios for Elemen tary and Briefer Courses

Aladdin, Wyo . Latrobe, Pa .

Bri stol,V a . lVIilwaukee , Wis .

Charleston, W . V a . Monterey, V a .

Cloud Peak— Fort Mc Morristown,“

Tenn .

Kinney,Wyo . Nevada Ci ty, Cal .

Colfax, Cal . Sundance, Wyo .

Danville,Ill . Walsenburg

, Colo .

Franklin Furnace,N . J . Warren

,Pa .

Holyoke,'

Mass . Winslow,Ark .

Joplin, M o .

B. Additional Folios for More Advanced Studen ts

Absaroka,Wyo . London, Ky .

Bidwell Bar, Cal . Mother Lode

,Cal .

Big Trees , Cal . Needle Mountains, Colo .

Bisbee,Ari z . Oelri chs

,S . D .

Burgettstown— Carnegie, Patoka, Ind .

Pa . Pawpaw— Hancock,M d .

Claysvi lle,Pa . Piedmont, W. V a .

Downievi lle, Cal . Pikeville

,Tenn .

Fayettevi lle,Ark . Pyrami d Peak

, Cal .

Gadsden, Ala . Bedding,Cal .

Globe, Ari z . Rockland,Me .

Harpers Ferry, V a . Si lverton

, Colo .

Lassen Peak, Cal . Stevenson

,Ala .

Lancaster— lWin eral Tishomingo, Ok . , (I . T .)Point; Wis .


that i t does outcrop just south of here,i n Secs . 23 and 26 .

Note the ages of the beds invo lved .

Win slow Folio

What is the explanation of the recurrence of beds (as

Ch l) i n the valley bottoms ?2. Can an uncon formi ty between the Missi ssippian and

the Pennsylvanian be detected on the map ?

At Cove Creek in the west central part of the map, two

faults cross each o ther . Is i t possible that they are con

temporaneous ? If n ot,what can be concluded as to the

amount of dip of the earlier on e ?

Tishomingo Folio

Make a structure section from Mill Creek (northwestpart of map) due southwest to the outcrop of Gsa .

Fayetteville Folio

Explai n in detai l the distribution of Carboniferous outcrops four mi les east of Johnson, i n the northwest part ofthe southeast rectangle .

Account for the Devonian outcrops i n the northern partof the southwestern rectangle .

2. Cumberland— Alleghany Plateau Region

Charleston Folio* 1 . What i s the general structure in this region ?

>W2 . Explai n the outcrops of Cs i n certai n valleys in thesouth central rectangle .

*3 . Explain the isolated outcrops of CbX east of Charleston .

4 . Study the relations of the Lower Carboniferous to theCarboniferous

,as shown on the Co lumnar Section Sheet


Latrobe Folio

1 . S tudy in detai l the outcrops along the line o f

Chestnut Ridge .

2. What i s the mean ing of the Cm patches within Ccm,

northwest central part of‘

map ?

3 . What i s the meaning of the Ccs outcrop within Ccmto the east of Nihi l i n the northwest part of the map ?

3 . The Appalachian Region

Warren F0 l

1 . Note the general character and structure of thePaleozoi c strata .

2. Noti ce especially the texture of the Carboniferous beds .a) Account for the j uxtaposition of Cpo and Ck at

several points in the east central part of the area .

b) Determine the thickness of Cch i n the eastern partof the sheet .

0 ) What is the mi nimum amount of post-Mississippianpre-Pennsylvanian erosion ?

(1) Give some idea of the time represented by thi sunconformi ty .

*4 . Explain the failure of Cps and Cpo to appear betweenCch and Cpc i n the east central part of the area . Takeinto consideration the lithological character of the formationsinvolved .

Mon terey Folio

Has folding or faulting been the more importantfactor in determining the arrangement of outcrops ?

Explain the i solated outcrops of Cpo i n the northcentra l rectangle .


What striking di fference i s there between the structure

of this region and that of the Morri stown quadrangle ?*4 . Explain the concentri c arrangement of outcrops with

Sj i n the center, near the eastern border of the south centralrectangle .

*5. From the data given on the map, what inference canbe drawn concerning the age of the igneous outcrops in thenortheast rectangle ?6 .

- Is there more than on e possible explanation for thedistribution of igneous outcrops shown in the northeastrectangle

7 . Note the structural positions of the valleys i n thedi fferent parts of the map .

8. What i s the structure of the high points ?

Bristol Folio

1 . Compare the attitude of the Si lurian and Devonianbeds with that of the Carboniferous beds .

Explain the distribution of the outcrops of Sa in thesoutheast portion of the map .

Study the contact of the Carboniferous, in the northwest part of the map, with the formations to the southeast .Follow thi s contact across the sheet

, an d determine thestructure whi ch occasions the various outcrops .*4 . Explain the i solated patches of Cn r and Cws i n thenorthwest corner of the map .

Explain the di stribution of the Devonian outcrops,Dc

an d c .

*6 . Why is there so little Devon ian at the surface ?Why are the outcrops of Devonian narrower here than

in the Monterey region ?


8. Why are there n o Carboniferous outcrops in the southeast part of the area ?

9 . What i s the meani ng of the outcrop marked SDh ,through the central portion of the map ?

10 . Determine the downthrow side of the faults just westof Raven s Nest, central rectangle .

1 1 . Note the relation of drainage to structure .

Franklin Fum ace Folio

*1 . Explain the interruption of Oj , 1% mi les north of

Lafayette,i n the west central rectangle .

Explain the offset in Oj in the north central part of

the central rectangle. How does thi s differ from the faultin 1

Work out the history of the Ordovi cian outcrops inthe northwest part of the west central rectangle .

4 . The N ew England Region

H olyoke Folio:

1 . What general structure i s suggested by the arrangement of outcrops i n the southwest rectangle ?*2. Explai n the form of the Sg outcrop i n the west centralrectangle

,including the peculiarity of outcrop at the

westernmost crossing of the Westfield River .How would you go to work in the field to determine

the age of the Cw formation ? Designate the most importantor most favorable places to V i si t .

What possible explanations can be given,from a study

of the Histori cal Geo logy Sheet, for the present distribu

tion of Cw outcrops ?How would you go to work in the field to determine

whether Cw i s intrusive or extrusive ?


*6 . Account for the outcrop of Sg i n the north central and

northwestern rectangles .

5. EastBase ofRocky Moun tain s

Wa lsen burg Falto

This may be regarded as a type of the Carboniferous outcrops at the east base of the Rocky Mountains . Study itsgeneral features .

Aladdin Folio1 . What feature occasions the intri cate outcrops in the

southwest corner of the sheet ?>l<2. From the Areal Geology Sheet

,determ ine the nature of

the chief feature at Sheep Mtn . Test your conclusion bythe structure section sheet .

Sundance Folio>t l . What i s the structure of Bear Lodge Mountains in thenorthwest corner of the area ?

What data were used in mapping Green Mtn .,Bald

M tn .,an d Strawberry Mtn . as laccoli ths on the structure

section sheet ?3 . From the structure section sheet

,what can be said of

the date of vulcanism north of Cement Ri dge ?

6 . The Rocky Mozmtain Region

Absaroka Folio (Cranda ll Sheet)

What are the possible ways of explaining the presentarrangement of Devon ian and Carboniferous outcrops ?Study especially in this connection the Sunlight Basin inthe east central rectangle . Why does not Cambrian appearin th i s rectangle ?


Work out the physi cal history of the region where theCarboniferous and Devonian appear .

Cloud P eah— Fort McKinn ey Folio>t l . What i s the date of the faulting at Bald Ridge, Justwest of the Fort M cKin n ey Military Reservation ?

Explai n the fai lure of the Paleozoi cs to outcrop alongthe Archean in two places northwest of Buffalo .

N eed le Moun tain s Folio

Work out the sequence of the faulting in the northeastcorner of the northwest rectangle . On the basi s of but threefaults

,i s the first on e reversed or normal ?

Silverton, Folio

Work out the physi cal history of this region to the closeof the Paleozoi c .

7 . The Arizon a, Region

Globe Folio>k’kl . Make a structure section from the letter B i n thename “Grani te Basin ” (northwestern part of map) , northeast to the letter “B” i n the name “Ruin Basin .

”

2 . Work out the structure along the section line AA fromthe Areal Geology Sheet

, an d then compare it with thestructure section .

Bisbee Folio

1 . Work out i n as great detai l as possible the history of thefaulted area about Bi sbee . Th e fault - diagram sheet willbe helpful .

Study the structure sections and interpret the physi calhi story of the region .


8. The California Region

Colfax Folio

What has been the chief factor i n determini ng thepresent form and distribution of Carboni ferous outcrops ?

Note thei r topographi c position .

2 . From the structure sections, noti ce the various formations with whi ch the Carboni ferous comes i n contact .*3 . What was the character of the topography of the regionat the time of the Na flows ?

N evad e City Special Folio

Note the scale,contour interval , and great detai l of thi s

map .

*1 . How may the present outcrops of Carboniferous beaccounted for ?2. From the sections

,determine with what formations the

Carboniferous comes in contact in thi s region .

3 . What i s the condition of the Carboniferous rocks in th i sregion

From the structure sections,can any generali zation be

made as to the location of the ore veins ?5. Note the location of the auriferous gravels and thei r

positions relative to the present drainage lines .

General Question s on the Ca liforn ia Region

What i s the general geographi c location of the areasshown on the folios ?

Which of the several Paleozoi c systems appear i n thi sregion ?

What i s the condition of the Paleozoi c formations inthis region ?


Th e folios li sted be low a lso show outcrops of th e later Paleozoi csy stems, and th ey may be used, if a more extended course is de sired ;or, fo lios of loca l intere st may be substituted for some of thoselisted above , or added to them .

Amity, Pa . John stown ,Pa .

Anthracite— Cre sted Butte , Colo . Kingston,Tenn .

Ashe vi lle , N. C . Kittanning, Pa .

A toka , Ok . (I . T. ) Knoxville,Tenn .

Ba ld Mountain— Dayton , Wyo . Laram ie— Sherman, Wyo .

Beaver, Pa . Li ttle Be lt Mountains, Mont .Briceville , Tenn . Livingston

,Mont .

Brownsville - Conne lsville , Pa . Loudon,Tenn .

Buckhannon , W . V a . Masontown - Uniontown,Pa .

Chattanooga, Tenn . Maynardvill e , Tenn .

Ch icago,Ill . McMin V ille , Tenn .

Cle ve land, Tenn . Mercersburg— Chambersburg,

Clifton, Ariz . Pa .

Coalgate , Ok . (I . T. ) Mount Stuart, Wash .

Columbia, Tenn . Muskoge e, Ok . (I . T. )

Cottonwood Falls, Kas . Newcastle, Wyo .

Ditn ey , Ind . New York City, N. Y.

Ebensburg, Pa . Ouray,Colo .

Edgemont, S . D . Pa ssaic, N. J

E lders Ridge , Pa . Pocahontas, V a .

E lkland— Tioga, Pa . Penobscot Bay , Me .

El Pa so, Texas . Pike s Peak, Colo .

E stillville , Ky . Placerville,Cal .

Foxburg— Clarion, Pa . Rale igh, W . V a .

Fort Benton , Mont . Ri chmond,Ky .

Franklin,W . V a . Ri co

,Colo .

Gaine s, Pa . Ringgold, Ga .

Greeneville , Tenn . Rogersvi lle,Pa .

Hartvill e , Wyo . Rome, Ga .

Hawley, Mass . Rura l V a lley,Pa .

Huntington, W . V a . Sacramento, Cal .Independence , Kas. Sewanee , Tenn .

Indiana, Pa . Sewickley,Pa .

Jackson , Cal . Smartsville , Cal .


Snoqualmie , Wash .

Sonora , Cal .Standingstone , Tenn .

Staunton, V a .

Tahlequah, Ok . (I . T. )Tazewe ll, V a .

Tenmile District, Colo .

Three Forks, Mont .Tinti c, Utah .

Wartburg, Tenn .

Watkins Glen- Catatonk, N Y.

Waynesburg, Pa .

Ye llowstone , Wyo .

EXERCISE X

TRIASSIC AND JURASSIC

I. FOLIOS TO BE STUDIEDA . Faltos for More Elemen tary and Briejer Courses

Belle Fourche, S . D . Philadelphia , Pa .

Holyoke,Mass . Pyrami d Peak

,Cal .

Laramie— Sherman,Wyo . Roseburg

,Ore .

Ouray,Co lo . Tenmile Distri ct, Colo .

Passai c, N . J Trenton,N . J

B. Addition al Faltos for More A dvanced Courses

Aladdin,Wyo . Harpers Ferry

,V a .

Bald Mountai n— Dayton , Mother Lode, Cal .

Wyo . Mount Mitchell,Colfax, Cal . Redding

, Cal .

Cranberry,N . C . Ri co

, Co lo .

Devils Tower,Wyo . Sonora

, Cal .

Edgemont,S . D . Telluride

, Colo .

Engineer Mountain,Colo . Truckee

,Cal .

Fort Benton,Mont .

II. OUTLINE FOR STUDYN ote .

— See DIRECTIONS , p . 35, and N ote, p . 1 1 .

1 . Bastem United States

H olyohe Folio1 . Can the emsten ce of a fault along the west margin of

the Jura -Trias be determined from the Histori cal Geo logySheet ? See the Structure Section Sheet .

55


2. Note the various sorts of igneous rocks associated withthe Jura -Trias .

What inference can be drawn from the shape of theoutcrop of the Ho lyoke diabase ? Carry this inference todetai ls .>I<4 . How might i t be determin ed in the fie ld whether or notthe two southern exposures of Jhp (east part of south centralrectangle) are parts of the same lava bed ?

a) Can i t be told from the Histori cal Geology Sheetwhether Jhp in the south central rectangle i s a dike, or aninterbedded lava sheet ?

b) How might it be determined in the field ?c) If Jhp i s a sheet, how may i t be determined whether

it was intrusi ve or extrusive ?6 . Th e relative age of Jhp an d Jb

,i n the east central

rectangle

7 . Study the relations of the various sorts of igneous rocksto on e another

,an d to the sedimentary rocks

,as shown by

the Structure Section Sheet .

Passaic Folio1 . Note the geographi c and physiographi c location of this

area .

2. Note the contact of the Triassi c with older rocks inthe northwest part of the area .

*3 . How would you determine in the fie ld whether or not

the contact of the Triassi c with older rocks i s a fault contact ?4 . How have the igneous outcrops influen ced the topog

raphy of the region ?Explain the hooked outcrops of Trw .

6 . Th e age of Trw and Trp ?

a) Can i t be told from the Areal Geology map whether


Trw,i s i n the form of dikes or interbedded lava sheets ?

b) How might i t be determined in the fie ld ?

c) If Trw i s a sheet, how may i t be determi ned whether

i t was intrusive or extrusive .

Tren ton Folio

1 . Note (a) the character of the Triassi c igneous rocks ,and (b) their relation to the sedimentary rocks .*2. Does the areal geology sheet (i ncluding legend) showwhether the igneous rocks were intrusive or extrusive ? Ifso, how ?

3 . Note the influence of the several members of theTri assi c system on the topography .

Philadelphia Folio:*1 . Account for the j uxtaposition of Trs with older beds

of varying ages on the Norri stown and Germantown sheets .2. Explain the isolated outcrops of Trs i n the southwest

corner of the central rectangle,Norri stown sheet .

How did the author of the folio know that the diabasedikes were Triassi c ?

2. The Western In terior Region

Belle Fourche Folio

1 . Note the location of th i s quadrangle with reference tothe Black Hills uplift .*2. Work out the early Mesozoi c history of the quadranglefrom the lithologi c characteri sti cs and the structural and

stratigraphic relations of the Spearfish and Sundanceformation s .

Tenmile Folio*1 . What structure could gi ve ri se to the peculiar relation


of sedimentary an d igneous rock outcrops shown on theeconomi c geology sheet ?2. Study the two Structure Section sheets .3 . Do the structure sections afford the data necessary for

determining whether the igneous rock i s intrusive or

extrusive

3 . The Rocky Moun tain Region

Oumy Folio

1 . Noti ce the stratigraphi c and structura l relations of theTriassi c an d Jurassic formations .

Draw a structure section from Baldy Peak,in the west

central rectangle,southwest to the edge of the sheet .

Determine the age of the east -west fault immediatelysouth of Ouray .

Interpret the relation of Tqm to the early Mesozoi cfo’rmations

,southwest of Ouray .

Rico Folio1 . What inference concerning the structure may be

drawn from the arrangement of the Triassi c and Jurassi cformations

Give the physi cal hi story of this region during the earlyMesozoi c time .

Is the Thm,near the south border of the quadrangle,

intrusive or extrusive ? Reasons for your answer ?

Laramie— She’

rman Folio:

1 . Note the location of the area .

*2. Explain the absence of the Sundance formation in the

Larami e quadrangle, an d i ts presence in the Sherman

quadrangle .


>13 . a) What fie ld evidence would you use to prove thepresence or absence of Permian in the Chugwater formation ?

b) If the lower Chugwater beds are of Permian age,

what are the stratigraphic relations of the Permi an beds ofthe region ?

0 ) Judging from thi s folio , would the Permian betterbe classed with the Paleozoi c or the M esozoi c ?

FortBen ton Folt o

1 . How are the peculiar outcrops of Je in the southeasternpart of the map, at Skull Butte and southwest of SkullButte, to be interpreted ?

4 . The Pacific Coast

Pyramid P eak Folio

Study the structure sections and compare them with theAreal Geology Sheet

,especially for the relation of igneous

rock to the Jura-Trias . (Th e Mother Lode, Co lfax, and

Sonora, Cal . , folios show simi lar condi tions . )

Bedding Folio:

Work out the early Mesozoi c history of the region froma study of the relations of the beds and their li thology .

2. Explain the peculiar shape of the Trh outcrops in theeast central and northeast rectangles .

Roseburg Folio1 . Note the relations of the Jr outcrops to the other forma

tions in the southwest rectangle . Th e possible interpretation of these outcrops ?

5. Gen eral Question s on the Triassic and Jumssic

(Jura Tfrias)

Compare the structural conditions of the Jura -Triasstrata in the di fferent regions .

EXERCISE XI

COMANCHEAN AND CRETACEOUS

I. FOLIOS TO BE STUDIED1 . The A tlan tic Coast.

Dover, Del . Patuxent, Md .

Frederi cksburg, V a . Trenton

,N . J

Passai c,N J Washington, D . C .

2. Texas

Nue cesUvalde

3 . The Great P lain s

Aberdeen— Redfie ld, S . D . Jamestown— Tower

,N . D .

Aladdin,Wyo . Laramie—Sherman, Wyo .

Belle Fourche, S . D . Olivet

, S . D .

Bi smarck,N D . Parker

, S . D .

Devi ls Tower,Wyo . Sundance

,Wyo .

4 . The Rocky Moun tain s

Bald Mountain— Dayton,Li ttle Belt Mountains

,

Wyo . Mont .Cloud Peak- Fort Mc Ri co

, Co lo .

Ki nney, Wyo . Spanish Peaks, Colo .

Elmoro, Colo . Telluri de

,Colo .

Engineer M ountain, C0 10 .

5. The Pacific Coast

Colfax, Cal . Lassen Peak, Cal .

Coos Bay, Ore . Roseburg, O re .


II . DIRECTIONSE lemen tary and Briefer Courses .

— Study enough of thefolios of each region li sted above to enable you to answer thequestions marked in the outline below .

Advanced Courses .

—Study all the folios li sted above,and

answer in writing questions marked and Study thetexts as well as the maps of the folios, wherever it i s necessaryto answer the questions fully .

N 0 te .

— See N ote, p . 1 1 .

m. QUESTIONS>l‘l . What are the stratigraphi c relations of the Cretaceousbeds to the overlying and underlying formations in thedifferent regions

,so far as shown in the folios ?

Prepare diagrams i llustrating the structural conditionsof the Cretaceous an d associated strata in the differentregions .*3 . What are the factors determining the general forms ofthe outcrops of Cretaceous in the different regions ?*4 . Prepare on e large diagram ,

or a series of smallerdiagrams

,i llustrating all the ways in which igneous rock i s

associated with the Cretaceous .What i s the age of the igneous rock associated with the

Cretaceous in the different regions , and how i s this agedetermined*6 . What kinds of rock represent the Cretaceous system i nthe different regions ?

What, i f any, products of economi c value do the Creta

ceous formations contain, as shown in the folio maps ?*8. Determine as closely as possible from the folios, thedate of origin of the Rocky Mountains . Read especially in


this connection the description of the Kingsbury conglom

crate, p . 8, Bald Mountain— Dayton folio .

Th e following folios may also be used to illustrate th e Comanch ean and Cre tace ous systems

A lexandria, S . D .

Anth racite— Cre sted Butte , Colo .

Atoka , Ok . (I . T. )Edgemont

, S . D .

E lk Point, S . D .

Fort Benton,Mont .

Hartvi lle, Wyo .

La Plata,Colo .

Livingston , Mont .Mitch e ll, S . D .

Mother Lode , Cal .Nepe sta, 0 0 1.Newcastle , Wyo .

New York City, N. Y .

Oe lri chs , S . D .

Ouray, Colo .

Ph ilade lph ia , Pa .

Pike s Peak,Co lo .

Placervi lle,Cal .

Port Orford , Ore .

Pueblo,Co lo .

Redding, Cal .San Luis

,Cal .

Santa Cruz, Cal .

Tishomingo, Ok . (I .

Thre e Forks,Mont .

Trucke e,Cal .

Walsenburg, Colo .

Ye llowstone,Wyo .

EXERCISE XII

TERTIARY

I. FOLIOS TO BE STUDIED

A . Folios for More E lemen tary and Briefer Courses

Aladdin,Wyo . Needle IVIoun tains

Bald Mountain - Dayton,

Ouray, Colo .

Wyo . Patuxent, Md .

Bi smarck,N D . Philadelphia

,Pa .

Bradshaw Mountains, Ari z . Ri co,Colo .

Choptank,Md . Snoqualmi e, Wash .

Cloud Peak— Fort M cKinn ey, St . Marys, Md .

Wyo . Sundance, Wyo .

Devils Tower,Wyo . Trenton

,N J

Dover, Del .

B. Addition al Falias for More Advanced Courses

Absaroka, Wyo . Nevada City, Cal .Big Trees, Cal . Nomini , Md .

Boi se,Idaho. Ri chmond, Ky.

Colfax, Cal . Roseburg, Ore .

Coos Bay, Ore . San Luis , Cal .Downievi lle

, Cal . Santa Cruz, Cal .Elk Point, S . D . Tacoma, Wash .

Little Belt Mountains, Walsenburg, Colo .

Mont . Washington , D . C .

Mother Lode, Cal“


II . DIRECTIONSElemen tary Course

— Study the folios of Group A above .

Omi t the General Questions . Prepare answers to all questions except those marked and answer in writing ques

tions markedAdvanced Course — Study all the folios of A and B above

,

using those of Group B especially for answering the GeneralQuestions . Th e folios should be studied with parti cularcare

,the structure sections and text s being used freely .

Answer in writing questions marked and

N 0 te .

— See N ote, p . 1 1 .

1 . The A tlan tic Coast

Patuxen t, St. Marys , Dover

,Philadelphia, Choptank, and

Tren ton Faltos*1 . What conclusions concerning the physi cal geography

of the Eocene period can be drawn from the character ofthe Eocene rocks ?

State the history of the Tertiary in th eu

region from thedescription of the Tertiary system . For detai ls

,read the

sections on Histori cal Geology in the fo lios .

2 . Black H ills and Great P lains

A laddin,D evils Tower

, Sundance, and Bismarck Faltos* 1 . What was the date of deformation of the Black Hills ?Reasons .

Th e relative ages of deformation an d igneous activi ty ?3 . What forms were taken by the igneous rocks ?*4 . Give in detail the events that led up to the formation

of Devi ls Tower (Devi ls Tower folio) .5


5. Elk Poin t Folio**a) Is there any suggestion of a more extensive distribution of the Tertiary than is shown on the map ?

**b) What would be the basi s for conclusions concerningsuch changes of drainage as those described in the Historyof the Tertiary ? (See text of folio . )

3 . The Bighorn Moun tains

Cloud P eah— Fort McKinney and Bald Moun tain— Dayton

Folios :*1 . From the geologi c map, determine as closely as may

be the age of the Bighorn Mountains .2. Read the descriptions of the Tertiary formations in thetexts of the folios, noting :

a) Th e character of the beds .b) Thei r topographic posi tion .

c) Their stratigraphic relation**d ) Read

“Age and Origin,” p . 9 , C loud Peak -Fort

M cKinn ey Folio . What,would you say of the probability

of the glacial origin of these beds ?

4 . The San Juan Moun tains

N eedle Moun tains, Ouray, and R500 FoliosName the chief events of the Tertiary period in

chronological order .What i s the relation of the deformation to the ore

deposits ? Which epoch of deformation is'

involved ?

*3 . From the Ri co Areal Geology Sheet, d etermine therelative ages of the igneous activi ty an d the faulting .

4 . Compare the San Juan uplift with the main area of

the Rocky Mountains, as to

a) Character of deformation .

b) Date of deformation ,


What are the stratigraphi c relations of the Telluride

conglomerate

5. The Cascade Moun tains

Sn oqualmie FolioDescribe the geographic conditions of the early Eocene .

*2. What was the chief event of the Tertiary period ?

6 . Arizona

Bradshaw Moun tains Folio*1 . Oi what rocks i s the Tertiary system composed ?

How were the ores deposited ?

3 . The age of the ores ?

7 . The Coast Ranges

San ta Cruz FolioLi st the principal events of thi s region during the

Tertiary period . Include geographi c changes, di astrophi cevents

,and igneous activi ty .

8. Gen eral Question s on the Tertiary

Adapt the general questions on the Cretaceous (p .

to the Tertiary formations, noting the following :a) Study in detai l (reading text) the Nomini , Washing

ton,Ri chmond, Tacoma, an d San Lui s folios .

b) In connection wi th the stratigraph i c relations of theTertiary beds

,study the col umnar sections in the more

recent folios .c) In connection with the igneous rocks associated

wi th the stratified Tertiary formations , study parti cularlythe following folios : Ouray and Walsenburg, Colo .

,

Absaroka, Aladdin, Devils Tower, and Sundance, Wyo .

,

EXERCISE XIII

PLEISTOCENE AND RECENT

I. FOLIOS TO BE STUDIEDA . Folios for More Elemen tary and Briefer Courses

Aberdeen -Re dfiel d, S . D . Lancaster— Mineral Point,

An n Arbor,lVIich . Wis .

Beaver,Pa . Masontown-Union town

,Pa .

Brown sville~ Conn e llsville , New York Ci ty, N . Y.

Pa . Passai c,N J

Burgettstown - Carnegie, Patoka,Ind .

Rockland,M e .

Chi cago, Ill . Sewi ckley,Pa .

Cloud Peak— Fort M cKin Tacoma, Wash .

ney,Wyo . Warren

,Pa .

Colfax, Cal . Watkins Glen— Catatonk,Gaines , Pa . N Y.

B. Addition a l Falias for More Advanced Courses

Bi smarck,N D . Jame stown - Tower

,N D .

Casselton— Fargo , N D . Latrobe,Pa .

Choptank,Md . Norfolk

, V a .

Claysville, Pa . Olivet, S . D .

Dover, Del . Ouray, Colo .

Elders Ri dge, Pa . Parker, S . D .

Elk Point, S . D . Patuxent

,Md .

Ellensburg, Wash . Philadelphia,Pa .

Engineer Mountain , Colo . St . Marys,Md .

Foxburg— Clarion,Pa . Trenton

,N . J

Flanklin Furnace,N J Waynesburg

,Pa .

Frederi cksburg, V a .


II . DIRECTIONSElemen tary Courses .

— Study only the folios of Group A .

Prepare answers to all questions n ot marked and answerin writing questions markedAdvanced Courses .

— Study all the folios of A and B above,

using those of Group B especially for answering the GeneralQuestions . Answer i n writing questions marked andN ote .

— In this exerci se, Surficial Geology sheets should be

studied where they are found in the folios,and free use

should be made of the folio texts .

III. QUESTIONS

Rockland Folio

*1 . What was the chief event of the Pleistocene period inthis distri ct as shown by the character of the Plei stoceneformations ?

What i s the maximum relative change of level recordedin the Rockland quadrangle

,since glaciation ? (See the

distribution of c of the Surficial Geology map, and

Marine Clay, p .

N ew York City Folio1 . Note the topographic expression of the Ptm belt on the

Brooklyn and Staten Island sheets (Surficial Geologysheets) .

*2. Th e origi n of the plain ofPsd across these quadrangles ?Note i ts influe n ce on the location of suburban towns .

3 . Outline the Plei stocene history of this region .

Passaic Folio1 . Study the Surficial Geology Sheet for various phases of

glacial deposits .

STRUCTURAL AND HISTORICAL GEOLOGY 71'

*2. Account for the southward loop of t east of the

Watchung M ountains .

3 . a) Note the distribution of Qk and e .

**b) How would you di stinguish between Qk and ein the fie ld ?

Franklin Fumace Folio

Work out a plausible hypothesi s for the origin of the

areas of Q d north of Frankli n Junction (central rectangle) ,east of Deckertown (north central rectangle) , and near

Northup (west central rectangle) .

Note the large kames, Q k, in the V i cinity of Hamburg

(east central rectangle) , and the lesser kames in association

with the other deltas, Q d . Has the association of kames

and deltas any significan ce ?

Draw diagrams which shall i llustrate the conditionsunder which the kame terraces of the quadrangle originated .

Work out a hypothesis for the peculiar area of Q k atOgdensburg . Note that i t extends directly across a

'

widevalley

,except for the narrow gap through which the Wallki ll

River runs . This gap i s probably post- glacial .

Watkin s Glen— Catatonk Folio

1 . Note the distribution of Qtd . Were the presentdrainage lines of thi s area developed before

,during

,or after,

the Wisconsin glacia l epoch ?*2. Explain the origin of the broad flat north of Elmi ra andwest of Horseheads

,Watkins Glen quadrangle .

3 . a) Note the location of eskers within and along streamvalleys .

**b) What i s the significance of thi s relation in con

nection with the origin of eskers ?


Fredericksburg and N oriolk Folios*1 . Interpret the Columbia formation, as shown in thesefo lios .

Ann Arbor Folio

Correlate the several beach ridges wi th the successivelines of drainage from thi s area during the retreat of theWi sconsin i ce sheet . (See pages 10 an d 1 1 of the text . )2. Note the location of thi s quadrangle with reference to

the Saginaw an d Huron - Erie i ce lobes (Fig . 5, p . 4 of the

text) .*3 . Explain the abrupt constri ction of the Huron valleyat Dexter, nine mi les northeast of An n Arbor .4 . Th e origin of the band of n and Q lc stretching from

An n Arbor southwest through Clinton and Tecumseh .

*5. Contrast the topography of this area with that of the

Patoka and Gaines quadrangles . Explain the differences .

Patoka Folio

After a care ful study of the legend,outline the Quater

nary history of this region .

2. Does the formation Tr about two mi les north of

Princeton, have any significan ce with reference to the timelimi ts within which the pres ent relief was developed ?

Chicago Folio

After a careful study of the topography, distribution ,and character of the Pleisto cene rocks

,and the elevation

and distribution of the shorelines, outline the glacia l andpost- glacial history of the region .

2. Account for the bowlder deposits in the northern partof the Desplaines quadrangle .

*3 . History (date of origin, source of sand, etc .) of


the dunes east and south of Evergreen Park, Calumet

quadrangle4 . There are several outcrops of rock in the area covered

by this fol io . From this, and from the further fact that thedrift is more than 100 feet deep at some po ints near theoutcrops

,what inference can be drawn as to the topography

of the Niagara limestone ?

Milwaukee Folio1 . Note the various kinds of glacial deposits in the

region .

2. What effect did the ice have on the drainage ?*3 . In what ways might the outcrop of Dm a long M ilwau

kee River 1 mile north of Milwaukee be explained ? Whichis the most probable explanation ?4 . Th e meaning of the appearance of Dm at the quarry

on the shore of Whitefish Bay ?How could the character of the surface of the Paleozo ic

rocks in this region be ascertained ?

Lancaster-M in era l Poin t Foh’

o

1 . a) What part of this region was glaciated during thePleistocene period ?

b) During which glacial epoch was it glaciated ?*2. Account for the areal d istribution

'

of Q1 (Lancasterquadrangle) .

Work out an explanation for the formation of theterraces

, Q t, in the valleys tributary to the Mississippi .

Jamestown Tower and Casselton - Fargo Faltos

1 . What was the origin of the Q la formation ? Of the

Qd formation ?Correlate the terrace deposits along Sheyenne River


(Casselton quadrangle) with successive stages of LakeAgassiz .

3 . Note the section on p . 3 , Casselton -Fargo folio .

Work out the probable history of the bowlders in the

Qb formation .

5. The source of the sand in the s formation ?

Aberdeen -Redfie ld Folio

1 . Study the four Areal Geo logy sheets in the fol io, forthe genera l resul ts of glaciation in the region .

2. Which of the Pleistocene ice sheets (early, la te) affectedthe region ?

3 . Note the topographic expression of the Qam and Q ld

formations .4 . What is the meaning of the Qod formation ?

Cloud P eak- Fort M cKinn ey Folio

1 . Note the character and distribution of the Quaternarydeposits .2. Note the d istribution

‘

of . Q1, ,C loud Peak Sheet, and

explain its origin .

3 . Give plausible hypotheses to explain the origin of Q t .

a) What fie ld evidence would you use to distinguishearlie r glacial drift from later glacial drift ?

b) How would you establish the age of Qvt , C loud

Peak Sheet ?

Gamy and Engmeer Moun tain Folios

Discuss the map evidence for two periods of glaciation

in this region .

2. Give some idea of the time that elapsed between thetwo epochs of glaciation .

STRUCTURAL AND HISTORICAL GEOLOGY 75‘

1 . Estimate the amount of post- glacial cutting by the

Yuba River near Emigrant Gap, northeast corner of central

rectangle .

Ellen sburg Folio

What is the origin of the Cowiche gravels ?

Tacoma Folio

*1 . State plausible hypotheses for the origin of the broaddepressions occupied by Puget Sound and tributary valleys .

Gen eral Question s

How many epochs of glaciation are represented inPennsylvania

,as shown by the fo lios Ditto in South

Dakota ? Ditto in Colorado ?Work out an hypothesis which satisfactorily explains

the constitution and distribution of the Carm ichael formation

,as shown in the western Pennsylvania fol ios .Outl ine the post-Miocene history of the Chesapeake

and Delaware Bay region, as shown by the constitution,the stratigraphic relations

,and the topographic distribution

of the post-Miocene deposits . Both deposits and changesof level are to be considered . See especially the Trenton

,

Philadelphia, Dover, Patuxent, and St . Marys fol ios .*4 . Locate three clearly d efin ed cases of drainage changesdue to sheet glaciation .

What, if any, products of economic value do thePleistocene glacial deposits contain ? Non - glacial ?6 . How would you determine in the field whether a

mountain valley had been glaciated ?M ake a list of n on - glacial or only indirectly glacial

Pleistocene deposits shown on the folios .

Chamberlin and Salisbury 5“

Geology

By THOMA S c. CHAMBERLIN AND ROLLIN D .

‘

SALI SBURY,

P rofessors in th e University of Ch icag o . (American Science Serie s, A dvanced Course . ) 3 V o lume s 8vo .

V olume I. Proce sse s and The ir Re sults.

‘

xix+654 pp.

V olume s II and III. Earth History . xxvi+692+x i+624 pp.

V 0 13 . II and [1] not J‘bld s eparate ly .

Chas . D Walcott , D irector of U. S . Geolog ica l S urvey :-I am

impre ssed W l th th e admirable plan o f th e work and with th e thoroughmanne r in which geological principle s and proce sse s and the ir re sultshave been pre sented. Th e text is written in an ente rtaining sty le ,and is supplemented by admirable illustrations, so that th e studentcannot fail to obtain a clear idea o f th e nature and work o f geologicalagencie s, o f th e pre sent status of the science , and o f th e sp irit Whichactuate s the working geologist.

Israel C . Russe‘l l , P rofessor in the Un iversity of M ich ig anTh e work is certainly monumental, and , like Ly e ll

’s Principle s o f

Geology , will in th e future , I am confid en t , be recognized as markingth e beginning o f a new pe riod in th e deve lopment o f th e Science of

th e earth.

R. S . Woodward, D irector of th e Carneg ie l n stitutz

’

org:- It is

admirable for its science , admirable for its 11te rary per fe ction, andadmirable for its unequalled illustrations.

College GeologyBy T. C. CHAMBERLIN AND R. D. SALI SBURY. (AmericanScience Se rie s . ) xvi+978 pp. 8y o .

A on e - volume text- book on th e line s of th e authors’ wide lyknown thre e - volume work. It supplie s ample material for th e av

e rage college course in geology .

T . C . Hopk ins , P rofesso? in Sy racuse Un iversity : —I find it so

far in advance o f th e othe r text- books I have se en that I de cided touse It m my class .

A . H . Ifurdue , Professor in th e Un iversity of A rhan sas :— Itprobably W 111 be th e standard co llege text - book in Ge ology forseve ral years to come .

E . N Lowe, D irector of Geolog ica l Survey , Jackson ,

— ItIS an unrivaled text- book for a brie f course in gene ral geology .

Salisbury’

s Physiography. Advanced Course

By ROLLIN D . SALISBURY,P rofessor in the University of Chi

cago . (Ame rican Science Se rie s, A dvanced Course . ) xx+77o

pp. 8vo . $3 .50 .

While p lanned for course s in college s and normal schools, itpresuppose s no previous study o f physical geography .

W . M . Davis , H arvard Un iversity :— It is an important addition

t o college lite rature , th e first book o f college grade on physiography.

Th e illustrations are for th e most part remarkably succe ssful andappropriate .

Salisbury’

s Physiograph y forH igh SchoolsBy ROLLIN D . SALI SBURY, P rofessor in m} University of Chi

cag o. (Ame rican Science Serie s, Brie fe r Course . ) viii+531pp . Large IZmO.

This is intended to cover th e work in physical geography as

g iven in th e first or second year o f the high school.

W . H . Hawkes , A nn A rbor (M ich ) H igh School .° — I am of the

opinion , afte r care ful examination o f th e leading Physio'

graphie son th e marke t, that Salisbury

’s Brie fer Course o f Physiography isin th e lead, in th e me thod o f treatment o f th e subj ect o f EarthS cience , its clearne ss o f pre sentation o f de tail, and e spe cially in th eways in which th e subj e ct matter is discussed in illustrative d iagrams.

Salisbury’

s Elementary PhysiographyBy ROLLIN D . SALISBURY, P r

gf essor in th e Un iversity of

Ch zkag o. (Ame rican Sc ience e ries, Eleme ntary Course . )xi+ 359 pp. 47 plate s . Large I zmo . $ 1 . 30 .

Th is is particularly we ll ad apted to first ye ar pupils and short enoughfor a h alf-y ear course if ne ed be .

C. L. Walton , Lahe V iew H igh School , Chicago -“ It would seem

that noth ing furth e r could be don e in th e way of pe rfe cting a text-book ine lementary physiography . A s we are to h ave bu t five month s of th is studyhe re after, I th ink no oth er book is so we ll adapte d to our n e ed s as th is one .

34 West 33d S tre et , New‘

York_

· PREFA CE This manual is the third of a series of outlines for labora tory work in general...

Documents

Transcript of · PREFA CE This manual is the third of a series of outlines for labora tory work in general...