Final Paleontological Identification/Evaluation Report · Final Paleontological...

Final Paleontological Identification/Evaluation Report

Dr. Fine Bridge Replacement Project

Del Norte County, California

EA: 01-43640

Contract Agreement No. 03A2369

Task Order #09

January 2017

For individuals with sensory disabilities, this document is available in Braille, large print,

on audiocassette, or computer disk. To obtain a copy in one of these alternate formats,

please call or write to Caltrans, Attn: Amanda Piscitelli, Environmental Coordinator,

Caltrans North Region Environmental, 1656 Union Street, Eureka, CA 95502

(707) 445-6431 Voice, or use the California Relay Service TTY number, 711.

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Table of Contents

Paleontological Identification/Evaluation Report January 2017 Dr. Fine Bridge Replacement Project i

Table of Contents

Chapter 1. Introduction ............................................................................................................... 1 1.1. Project Location and Description ..................................................................................... 1 1.2. Dr. Fine Bridge Demolition and Construction ................................................................. 2

Chapter 2. Significance .............................................................................................................. 6 2.1. SVP Categories of Paleontological Potential ................................................................... 7 2.2. Caltrans SER Categories of Sensitivity ............................................................................ 8

Chapter 3. Laws, Ordinances, Regulations, and Standards ...................................................... 10 3.1. Federal LORS ................................................................................................................. 10 3.2. State LORS ..................................................................................................................... 11 3.3. County LORS ................................................................................................................. 11 3.4. City LORS ...................................................................................................................... 13 3.5. Professional Standards.................................................................................................... 13

Chapter 4. Key Personnel, Methods, and Assessment Criteria ................................................ 14 4.1. Key Personnel ................................................................................................................. 14 4.2. Resource Inventory Methods .......................................................................................... 15 4.3. Field Survey ................................................................................................................... 16 4.4. Paleontological Resource Assessment Criteria .............................................................. 16

Chapter 5. Affected Environment ............................................................................................. 19 5.1. Geographic Location ...................................................................................................... 19 5.2. Regional Geologic Setting .............................................................................................. 19 5.3. Project Geologic Setting ................................................................................................. 21

5.3.1. Franciscan Complex (Late Jurassic to Early Cretaceous) ........................................... 21 5.3.2. Quaternary Stream Terrace (Pleistocene to Early Holocene) ..................................... 23 5.3.3. Quaternary Alluvium and Fluvium (Holocene) .......................................................... 24

Chapter 6. Results ..................................................................................................................... 26 6.1. Geologic Map Inventory and Field Survey .................................................................... 26 6.2. Paleontological Resource Inventory ............................................................................... 26

6.2.1. Franciscan Complex ................................................................................................... 27 6.2.2. Quaternary Stream Terrace (Pleistocene to Early Holocene) ..................................... 27 6.2.3. Quaternary Alluvium and Fluvium (Holocene) .......................................................... 28 6.2.4. Summary ..................................................................................................................... 28

Chapter 7. Environmental Consequences ................................................................................. 29 7.1. Potential Impacts from Project Construction .................................................................. 29 7.2. Cumulative Impacts ........................................................................................................ 30

Chapter 8. Proposed Monitoring, Collection, and Treatment Measures .................................. 31 8.1. Retain a Professional Paleontologist and Prepare a PMP ............................................... 31 8.2. Provide Worker Education on Paleontological Resources ............................................. 31 8.3. Result of Implementation ............................................................................................... 32

Chapter 9. References ............................................................................................................... 33

Appendix A. Standard Procedures for the Assessment and Mitigation of Adverse Impacts to

Paleontological Resources .......................................................................................................... 41

Appendix B. Conditions of Receivership for Paleontological Salvage Collections ................. 53

List of Tables

Paleontological Identification/Evaluation Report January 2017 Dr. Fine Bridge Replacement Project ii

List of Figures

Figure 1. Project Region ................................................................................................................... 2 Figure 2. Project Location ............................................................................................................. 20 Figure 3. Geologic Map of the Project Area .................................................................................. 21 Figure 4. Franciscan Complex Graywacke with Intercalated Shale ............................................... 23 Figure 5. Quaternary Stream Terrace Deposits .............................................................................. 24 Figure 6. Holocene Fluvial Deposits in the Active Smith River Channel Overlying Franciscan

Complex Greywacke ....................................................................................................... 25

List of Tables

Table 1. Paleontological Potential of Geological Units Found in the Project Area.. ..................... 26

List of Tables

Paleontological Identification/Evaluation Report January 2017 Dr. Fine Bridge Replacement Project iii

List of Abbreviated Terms

Caltrans California Department of Transportation

CEQA California Environmental Quality Act

CIDH Cast in Drilled Hole

CISS Cast in Steel Shell

FW Falsework

LORS Laws, Ordinances, Regulations, and Standards

PM Post Mile

NEPA National Environmental Protection Act

PG Professional Geologist

PIR Paleontological Identification Report

PER Paleontological Evaluation Report

P.L. Public Law

PRC PaleoResource Consultants

SER Standard Environmental Reference

SR State Route

SVP Society of Vertebrate Paleontology

UCMP University of California Museum of Paleontology

U.S.C. United States Code

USGS United States Geological Survey

Chapter 1. Introduction

Paleontological Identification/Evaluation Report January 2017 Dr. Fine Bridge Replacement Project 1


The purpose of this Paleontological Identification/Evaluation Report (PIR/PER) is to

provide an assessment of potential adverse impacts on paleontological resources resulting

from earth-moving activities related to construction of the Dr. Fine Bridge Replacement

Project (Project). PaleoResource Consultants (PRC) was retained by ICF International to

prepare this report. This PIR/PER meets all requirements of the National Environmental

Policy Act (NEPA), the California Environmental Quality Act (CEQA), the California

Department of Transportation (Caltrans) guidelines detailed in the Standard

Environmental Reference (SER) (Caltrans 2016), and the standard procedures for

mitigating adverse construction-related environmental impacts on paleontological

resources established by the Society of Vertebrate Paleontology (SVP) (1996, 2010)

(Appendices A and B).

1.1. Project Location and Description

Caltrans District 1/North Region proposes to replace the Dr. Fine Bridge on State Route

(SR) 101 between Post Mile (PM) 35.8 and PM 36.3 in Del Norte County, approximately

9 miles north of Crescent City, California (Figure 1). The Dr. Fine Bridge is physically

deficient and functionally obsolete and does not meet current Caltrans requirements. The

bridge will be replaced with a structure that meets current material, geometric, scour and

seismic design standards.

Bridge replacement would involve demolition of the existing bridge and replacement

with new structures, a two-lane highway, an acceleration lane, and standard shoulders.

The typical section for the new bridge is two 12-foot lanes, 8-foot shoulders, and a 6-foot

pedestrian walkway located on the west side. Project activities would include ground

disturbance during slope, abutment, and pedestrian walkway excavations; grading at

equipment staging areas and for an infiltration basin; construction of coffer dams;

auguring for new piers; and pile driving for abutment support. The equipment staging

area would be located northwest of the Dr. Fine Bridge. Temporary construction

easements would be located along the shoulders of SR 101 south of the bridge.



Figure 1. Project region. Scale approximately 1:700,000. Map modified from the U.S. Geological Survey 30' x 60' Crescent City Quadrangle.

1.2. Dr. Fine Bridge Demolition and Construction

The replacement of the Dr. Fine Bridge would likely occur in the following sequence.

Utility Relocation—Phone and cable, fiber optic, and electrical transmission

lines and a U.S. Geological Survey (USGS) Gauging Station would have to be

temporarily relocated during bridge demolition and construction.

Preparation for Construction—Placement of construction signage, development

of a Storm Water Pollution Prevention Plan, and placement of Environmentally

Sensitive Area signs would also be accomplished before Project construction.

Clear and Grub—All vegetation within the right-of-way, unless otherwise noted,

would be removed, converted to duff, and stockpiled for use in re-vegetation.



Drainages may need to be relocated/modified, and a dewatering system and

infiltration basin would be utilized.

Work Trestles—Two 35- to 45-foot-wide temporary construction trestles would

be erected onsite, with one trestle flanking either side of the bridge. In addition,

temporary finger trestles will be connected to the construction trestles. The

construction and finger trestles will be used for construction of the temporary

detour and the construction of the new bridge.

Build Detour—The entire detour would consist of a south tie-in, south approach,

existing relocated main spans, north tie-in, and north approach. Both the north and

south tie-ins would consist of earthwork to match the lower detour elevation to

the higher elevation of the new highway grade. The south approach would be new

construction with a pre-cast I-girder super structure and Cast in Steel Shell (CISS)

pile foundations. The abutment would be supported by driven H-piles. A steel

sheet pile wall would be constructed to reduce the height of the outboard wing

wall. The sheet piles are expected to be approximately 50 feet long. The existing

relocated main spans would consist of the existing steel I-girder super structure

and a combination of CISS or Cast in Drilled Hole (CIDH) piles depending on the

distance from the south side of the river. CISS piles are proposed for the southern

supports and would be installed with a vibratory hammer as far as possible and

oscillated in or use center relief drilling methods for the remainder. The northern

supports would be CIDH piles with rock sockets due to geological conditions.

The piles would be installed with a vibratory hammer as far as possible and

oscillated the rest of the way. Once the steel shells are in place the rock sockets

would be drilled below. South Bank Road would be realigned slightly to the south

of its current alignment to avoid the detour piers and would be placed back in its

original location after the new bridge is completed.

Jack-N-Slide—There would be a substructure system constructed to support the

Jack-N-Slide bridge moving apparatus. This would consist of translation beams

supported by the existing piers and newly constructed detour piers orientated in

the direction the bridge would move. Steel piles would be driven into the channel

at the existing piers for support once the existing piers are cut. Piles would also be

driven in the channel to support the midspan of the translation beams. The north

approach would be new construction with pre-cast I-girder super structure and

CIDH piles with rock sockets constructed in the same manner as the CIDH piles

for the northern supports of the main spans. The abutment would be supported by

driven H-piles. A steel sheet pile wall would be constructed to reduce the height

of the outboard wing wall.

Demo Old Bridge—The existing steel bracing and steel girders would be cut and

removed in portions with a crane positioned on the temporary trestle or leveled



ground surface. Foundations supporting the existing bridge to be removed include

14 concrete bents in the overbank area and 5 piers in the channel, as well as two

abutments and seismic retrofit piles on land. The 14 bents that are outside the

river channel would have their concrete columns and foundations removed.

Excavations for the bents would be backfilled with native material and graded to

finish grade. The five piers in the river channel would be removed down to the

pile caps, leaving the pile caps in place, if possible. If the old foundations must be

removed completely, cofferdams would be required to remove the pile cap and H-

piles for each pier. The existing steel H-piles would be cut off below channel

bottom, leaving the rest in place.

Build New Bridge—Construction on the new bridge would commence once

traffic is travelling on the east detour and the old bridge is removed. Construction

and finger trestles would provide the working surface in addition to cofferdams

for building the new bridge. The foundations of the three piers would be the first

order of work in constructing the new bridge. Coffer Dams (Sheet Pile walls)

would be used on all three pier locations. Once the three foundations are

complete, pier construction would follow. Lastly, Falsework (FW) would be

erected to allow for construction of the bridge’s superstructure.

The foundation for each pier includes two 8-foot diameter CIDH piles. These

piles go from just below ground down to bedrock, and a 7-foot diameter rock

socket would tie the CIDH pile into the bedrock below. A crane-mounted drill

rig with a rock auger would likely be used to drill the piles while on the

trestles. A drilling bucket may be used to extract material that cannot be

removed with an auger.

There would be two 8-foot diameter columns at each of the three pier

locations.

FW is needed to temporarily support the superstructure construction. The FW

foundation would likely be a combination of driven steel or wooden piles and

concrete and/or timber pads if over land. Pile driving equipment would be

used to construct the FW. The FW piles would be installed in the same

manner as the steel pipe piles, vibrated in 50% of the assumed 50-foot length,

and then driven to final elevation using an impact hammer. Abutments 1 and 5

would be located at the south and north ends of the bridge, respectively. The

abutments would likely be concrete seats with steel H piles. Reinforced

concrete footings would be constructed to cap the steel H piles if they are

possible. Concrete abutment seats would be placed on the abutment footings.

Because of the closeness of bedrock, it may be determined during the

construction of Abutment 5 that H piles will not work; alternatively, 4-foot-



diameter CIDH piles comparable to the ones used for the detour supports

could be used.

The superstructure and bridge deck would be constructed with concrete forms

for the bottom slab and girders, reinforcing steel, post-tensioning ducts, and

reinforced concrete backwalls at the abutments.

Switch Traffic to New Bridge—Traffic would be moved on to the new bridge.

Once all of the structure and roadway work is accomplished that does not affect

the east detour. Even with traffic travelling on the new bridge, construction work

would continue with completing the roadway tie-ins and east retaining walls. The

east detour would be demolished via access from the Construction Trestle.

Demo Detour Bridge—The contractor would be required to design a detour

bridge demolition plan for review and approval by the Resident Engineer.

Chapter 2. Significance



Paleontological resources (fossils) are the remains or traces of prehistoric plants and

animals. Fossils are important scientific and educational resources because of their use in

(1) documenting the presence and evolutionary history of particular groups of extinct

organisms, (2) reconstructing the environments in which these organisms lived, and (3)

determining the relative ages of the strata in which they occur and of the geologic events

that resulted in the deposition of the sediments that entombed them.

As defined by the SVP (2010), a paleontological resource can be scientifically significant

(i.e., unique) if it:

consists of identifiable vertebrate remains, large or small

represents uncommon plant, invertebrate, or trace fossils

provides important taphonomic, taxonomic, phylogenetic, paleoecologic,

stratigraphic, or biochronologic information

In common with other environmental disciplines, such as archaeology and biology

(specifically in regard to listed species), SVP (2010) considers any fossil specimen

scientifically significant unless demonstrated otherwise, and, therefore, protected by

environmental statutes (Chapter 3). This position is held by SVP because fossils are

uncommon and only rarely will a fossil locality yield a statistically significant number of

specimens representing the same species. In fact, some types of fossils, such as all fossil

vertebrates, are so uncommon that, in most cases, each fossil specimen found will

provide additional important information about the characteristics or distribution of the

species it represents. An individual fossil specimen is considered scientifically important

if it is a:

type or topotypic specimen

member of a rare species

species that is part of a diverse assemblage

skeletal element different from, or a specimen more complete than, those now

available for that species

Identifiable land mammal fossils are considered scientifically important because of their

potential use in providing accurate age determinations and paleoenvironmental

reconstructions for the sediments in which they occur. Moreover, vertebrate remains are

comparatively rare in the fossil record. Although fossil plants are usually considered of



lesser importance because they are less helpful in age determination and more abundant,

they are actually more sensitive indicators of their environment and as sedentary

organisms are more valuable than mobile animals for paleoenvironmental

reconstructions. For marine sediments, invertebrate and marine algal fossils, including

microfossils, are scientifically important for the same reasons that land mammal and/or

land plant fossils are valuable in terrestrial deposits. The value or importance of different

fossil groups varies depending on the age and depositional environment of the

stratigraphic unit that contains the fossils.

2.1. SVP Categories of Paleontological Potential

In its standard procedures for assessment and mitigation of adverse impacts to

paleontological resources, the SVP (2010) established four categories of sensitivity for

paleontological resources: high, low, undetermined, and no potential.

High Potential. Stratigraphic units in which vertebrate or significant invertebrate fossils

or significant suites of plant fossils have been previously found have a high potential to

produce additional significant non-renewable fossils and are therefore considered to be

highly sensitive. In keeping with the significance criteria of the SVP (2010), all

stratigraphic units in which vertebrate fossils have previously been found have a high

potential for significant paleontological resources. Full-time monitoring is recommended

during any project-related ground disturbance in stratigraphic units with high potential.

Low Potential. Stratigraphic units that have not been known to produce fossils in the past

or have only nonsignificant, often poorly preserved invertebrate or plant fossils are

considered to have low potential for significant paleontological resources. Low potential

units also include strata where fossil preservation is the exception rather than the rule.

Monitoring is usually not recommended nor needed during project construction within a

stratigraphic unit with low potential, but, depending on other environmental factors, part-

time monitoring may be warranted.

Undetermined Potential. Stratigraphic units that have not had any previous

paleontological resource surveys or any fossil finds are considered to have undetermined

sensitivity. After reconnaissance surveys, observation of artificial exposures (such as road

cuts) and natural exposures (such as stream banks), and possible subsurface testing (such

as auguring or trenching), an experienced, professional paleontologist can often

determine whether the stratigraphic unit should be categorized as having high, low, or no

potential.



No Potential. Some rock units, such as plutonic igneous or high-grade metamorphic

rocks, have no potential to produce fossil resources. These rock units generally do not

require any protection or mitigation measures.

2.2. Caltrans SER Categories of Sensitivity

In its SER (Caltrans 2016), Caltrans uses a tripartite scale of potential for paleontological

resources: high, low, and no potential.

High Potential. Rock units which, based on previous studies, contain or are likely to

contain significant vertebrate, significant invertebrate, or significant plant fossils. These

units include, but are not limited to, sedimentary formations that contain significant

nonrenewable paleontological resources anywhere within their geographical extent and

sedimentary rock units temporally or lithologically suitable for the preservation of fossils.

These units may also include some volcanic and low-grade metamorphic rock units.

Fossiliferous deposits with very limited geographic extent or an uncommon origin (e.g.,

tar pits and caves) are given special consideration and ranked as high potential. High

potential includes the potential for containing 1) abundant vertebrate fossils; 2) a few

significant fossils (large or small vertebrate, invertebrate, or plant fossils) that may

provide new and significant taxonomic, phylogenetic, ecologic, and/or stratigraphic data;

3) datable organic remains older than Recent, including Neotoma middens; or 4) unique

new vertebrate deposits, traces, and/or trackways. Areas with a high potential for

containing significant paleontological resources require monitoring and mitigation.

Low Potential. This category includes sedimentary rock units that 1) are potentially

fossiliferous but have not previously yielded significant fossils; 2) have not yet yielded

fossils but possess a potential for containing fossil remains; or 3) contain common and/or

widespread invertebrate fossils if the taxonomy, phylogeny, and ecology of the species

contained in the rock are well understood. Sedimentary rocks expected to contain

vertebrate fossils are not placed in this category because vertebrates are generally rare

and found in more localized stratum. Rock units designated as low potential generally do

not require monitoring and mitigation. However, as excavation for construction gets

underway, it is possible that new and unanticipated paleontological resources might be

encountered. If this occurs, a Construction Change Order must be prepared in order to

have a qualified Principal Paleontologist evaluate the resource. If the resource is

determined to be significant, monitoring and mitigation is required.



No Potential. Rock units of intrusive igneous origin, most extrusive igneous rocks, and

moderately to highly metamorphosed rocks are classified as having no potential for

containing significant paleontological resources. For projects encountering only these

types of rock units, paleontological resources can generally be eliminated as a concern

when the Preliminary Environmental Analysis Report is prepared and no further action

taken.

Chapter 3. Laws, Ordinances, Regulations, and Standards



Paleontological resources are classified as non-renewable scientific resources and are

protected by several federal and state statutes (California State Historic Preservation

Office 1983; Marshall 1976; West 1991; Fisk and Spencer 1994; Gastaldo 1999), most

notably by the 1906 Federal Antiquities Act and other subsequent federal legislation and

policies and by the State of California’s environmental regulations (CEQA). Professional

standards for assessment and mitigation of adverse impacts on paleontological resources

have been established by the SVP (1996, 2010). Design, construction, and operation of

the proposed Projects need to be conducted in accordance with laws, ordinances,

regulations and standards (LORS) applicable to paleontological resources. Therefore, the

LORS applicable to paleontological resources are briefly summarized below, together

with SVP professional standards.

3.1. Federal LORS

Federal legislative protection for paleontological resources stems from the Antiquities

Act of 1906 (Public Law [P.L.] 59-209; 16 United States Code [U.S.C.] 431 et seq.; 34

Statute 225), which calls for protection of historic landmarks, historic and prehistoric

structures, and other objects of historic or scientific interest on federal land. The

Antiquities Act of 1906 forbids disturbance of any object of antiquity on federal land

without a permit issued by the responsible managing agency. This act also establishes

criminal sanctions for unauthorized appropriation or destruction of antiquities. The

Federal Highways Act of 1958 specifically extended the Antiquities Act to apply to

paleontological resources and authorized the use of funds appropriated under the Federal-

Aid Highways Act of 1956 to be used for paleontological salvage in compliance with the

Antiquities Act and any applicable state laws (Fisk and Spencer 1994). The language in

the Highways Act makes it clear that Congress intended that, to be in compliance with

the Antiquities Act, highway construction projects must protect paleontological

resources. Federal protection would apply to this project if it is federally funded through

the Federal Highway Administration.

In addition to the Antiquities Act and the Paleontological Resources Preservation Act,

other Federal statutes protecting fossils include the following. The National

Environmental Policy Act of 1969 (P.L. 91-190, 31 Statute 852, 42 U.S.C. 4321-4327)



requires that important natural aspects of our national heritage be considered in assessing

the environmental consequences of any proposed project. The Federal Land Policy

Management Act of 1976 (P.L. 94-579; 90 Statute 2743, U.S.C. 1701-1782) requires that

public lands be managed in a manner that will protect the quality of their scientific

values. Paleontological resources are also afforded federal protection under Code of

Federal Regulations Title 40, Section 1508.27 as a subset of scientific resources.

3.2. State LORS

Guidelines for the Implementation of CEQA, as amended September 7, 2004, (Title 14,

Chapter 3, California Code of Regulations: 15000 et seq.) define procedures, types of

activities, persons, and public agencies required to comply with CEQA, and include as

one of the questions to be answered in the Environmental Checklist Form (Section 15063

and Appendix G, Section V, Part c) the following: “Will the proposed project directly or

indirectly destroy a unique paleontological resource or site?”

The CEQA lead agency having jurisdiction over a project is responsible to ensure that

paleontological resources are protected in compliance with CEQA and other applicable

statutes. Caltrans is the CEQA lead agency with the responsibility to ensure that fossils

are protected during construction on this project. CEQA Section 21081.6 requires that the

lead agency demonstrate project compliance with mitigation measures developed during

the environmental impact review process.

Other state requirements for paleontological resource management are in California

Public Resources Code Chapter 1.7, Section 5097.5 (Statutes. 1965, Chapter 1136, Page

2792). This statute defines any unauthorized disturbance or removal of a fossil site or

fossil remains on public land as a misdemeanor and specifies that state agencies may

undertake surveys, excavations, or other operations as necessary on publicly owned lands

to preserve or record paleontological resources. This statute applies to the Project because

impacts would occur on California state-owned lands.

3.3. County LORS

California Planning and Zoning Law requires each county and city jurisdiction to adopt a

comprehensive, long-term general plan for its development. The general plan is a policy

document designed to give long range guidance to those making decisions affecting the

future character of the planning area. It represents the official statement of the



community's physical development as well as its environmental goals. The general plan

also acts to clarify and articulate the relationship and intentions of local government to

the rights and expectations of the general public, property owners, and prospective

investors. Through its general plan, the local jurisdiction informs these groups of its

goals, policies, and development standards; thereby communicating what must be done to

meet the objectives of the general plan. State planning law requires each jurisdiction to

identify environmental resources and to prepare and implement policies which relate to

the utilization and management of these resources.

The Del Norte County General Plan (Del Norte County 2003) addresses paleontological

resources in its general plan. Goal 5.H states the county’s intention “to encourage

identification, protection, and achievement of Del Norte County’s important historical,

archaeological, paleontological, and cultural sites and activities, and their contributing

environment”.

To achieve this goal, Del Norte County has instituted several policies relating to

paleontological resources.

Policy 5.H.2 states that “The County shall continue to require that discretionary

development projects identify and protect from damage, destruction, and abuse,

important historical, archaeological, paleontological, and cultural sites and their

contributing environment. Such assessments shall be incorporated into a countywide

cultural resource database”.

Policy 5.H.5 encourages “the cooperation of the owners of cultural and paleontological

resources to treat these resources as assets rather than liabilities, and encourage the

support of the general public for the preservation and enhancement of these resources”.

Policy 5.H.9 requires “that discretionary development projects are designed to mitigate

potential impacts to significant paleontological or cultural resources whenever possible.

Determinations of impacts, significance, and mitigation shall be made by qualified

archaeological (in consultation with recognized local Native American groups),

historical, or paleontological consultants, depending on the type of resource in question”.

These policies and the goal are intended to further require that projects be assessed for

their impacts to significant paleontological resources and that these impacts be mitigated.

Additionally, the assessment and mitigation recommendations must be made by a

qualified expert.



3.4. City LORS

The Project is in an unincorporated portion of Del Norte County. Accordingly, the

Project is not subject to any city laws, ordinances, or regulations.

3.5. Professional Standards

The work performed for this report conforms to SVP standard procedures (SVP 2010).

The SVP is a national scientific organization of professional vertebrate paleontologists.

The SVP standard procedures outline acceptable professional practices in the conduct of

paleontological resource assessments and surveys, monitoring and mitigation, data and

fossil recovery, sampling procedures, and specimen preparation, identification, analysis,

and curation (SVP 2010). The SVP’s standard procedures were approved by a consensus

of professional paleontologists and are the standard against which all paleontological

monitoring and mitigation programs are judged. Many federal and state regulatory

agencies have either formally or informally adopted the SVP’s standard procedures for

the mitigation of construction-related adverse impacts on paleontological resources,

including both federal (e.g., Federal Energy Regulatory Commission, U.S. Forest

Service, Bureau of Land Management, National Park Service) and state agencies (e.g.,

California Energy Commission, California Public Utilities Commission, Caltrans).

Briefly, SVP standard procedures require that each project have literature and museum

archival reviews, a field survey, and, if there is a high potential for disturbing significant

fossils during project construction, a mitigation plan that includes monitoring by a

qualified paleontologist to salvage fossils encountered, identification of salvaged fossils,

determination of their significance, and placement of curated fossil specimens into a

permanent public museum collection (such as the designated California state repository

for fossils, the University of California Museum of Paleontology [UCMP]).

Chapter 4. Key Personnel, Methods, and Assessment Criteria



4.1. Key Personnel

Dr. Lanny H. Fisk, PhD, PG, Project Paleontologist has over 30 years experience as a

professional paleontologist and 25 years as a paleontological consultant doing

paleontological resource impact assessments and surveys, preparing CEQA and NEPA

environmental documents and mitigation measures, designing and managing

environmental compliance monitoring programs, and coordinating and consulting with

state and federal resource agencies to resolve environmental concerns regarding

paleontological resources. He has been a consulting paleontologist on numerous large

earth-moving construction projects in California, including pipelines, power plants,

highways, tunnels, fiber-optic cables, landfills, and housing developments. These projects

have involved extensive coordination and consultation with project sponsors, other

consulting firms, and permitting agencies; adherence to strict delivery schedules; and

completion within specified budget limits. Dr. Fisk has also taught paleontology courses

at the university/college level and authored or co-authored a number of scientific research

contributions on paleontological resources. His experience includes preparing

paleontological resource impact assessments and paleontological resource monitoring and

mitigation programs. Dr. Fisk has a PhD with emphasis in paleobiology, plus all the

coursework and research for a PhD in Geology. He holds a Bureau of Land Management

Scientific Paleontological Collecting Permit, which demonstrates the qualification to do

Federal Antiquities Act studies.

Other PRC personnel who worked on this assessment include Dr. David M. Haasl, PhD;

Stephen J. Blakely; David F. Maloney; and Brendan J. Pfeiffer. Dr. Haasl has 5 years’

experience as a museum scientist at UCMP and is the author of several scientific papers

on paleontology, specifically on Cenozoic marine mollusks. He has a PhD in

paleobiology from the University of California, Davis, and a MS in paleontology from

Western Washington University. He has contributed to the preparation of paleontological

resource impact assessments, field surveys, and paleontological mitigation and

monitoring plans. David F. Maloney has a BSc in Geology from California State

University, Chico, where he is presently attending graduate school. He is a Staff

Paleontologist with PRC and has 15 years’ experience in paleontological mitigation,

including field assessments, paleontological monitoring, fossil recovery and cataloging,

report generation, laboratory preparation of fossils, and identification of micro- and



macrofossils. Stephen J. Blakely is a Staff Paleontologist with PRC and has nearly 10

years experience working in paleontological mitigation performing field assessments,

construction monitoring, fossil recovery, and laboratory preparation and has contributed

on many paleontological assessments, mitigation plans, and mitigation reports. He has a

background in geology from study at the University of California, Davis, and has several

years experience working in the construction industry and geological experience working

in the sedimentology laboratory at the University of California, Davis. Brendan J. Pfeiffer

has a BSc in Geology from the University of Northern Colorado. He is a Staff

Paleontologist with PRC and has 2 years’ experience working in paleontological

mitigation performing field assessments, construction monitoring, fossil recovery, and

laboratory preparation and has contributed on paleontological assessments, and

mitigation reports.

4.2. Resource Inventory Methods

To develop a baseline paleontological resource inventory of the Project and surrounding

area and to assess the potential paleontological productivity of each stratigraphic unit

present, the published as well as available unpublished geological and paleontological

literature was reviewed and stratigraphic and paleontologic inventories were compiled,

synthesized, and evaluated. These methods are consistent with SVP (2010) standard

procedures for assessing the importance of paleontological resources in areas of potential

environmental effect. No subsurface exploration was conducted for this assessment.

Geologic maps and reports covering the bedrock and surficial geology of the Project

vicinity were reviewed to determine the surface and subsurface rock units, assess the

potential paleontological productivity of each rock unit, and delineate their respective

areal distribution in the Project area. The number and locations of previously recorded

fossil sites from rock units exposed in and near the Project and the types of fossil remains

each rock unit has produced were evaluated based on published and unpublished

geological and paleontological literature. The literature review was supplemented by

archival record searches conducted at UCMP and by e-mail communication with experts

on local paleontology at California State University, Humboldt, for additional

information regarding the occurrence of fossil sites and remains on and near the Project

site.



4.3. Field Survey

A field survey, which included visual inspection of exposures of potentially fossiliferous

strata in the Project area, was conducted on September 14, 2016. The field survey was

conducted by PRC Staff Paleontologists Brendan J. Pfeiffer and Stephen J. Blakely. The

purpose of the field survey was to document the presence of sediments suitable for

containing fossil remains and the presence of any previously unrecorded fossil sites.

4.4. Paleontological Resource Assessment Criteria

Under SVP (2010) criteria, a stratigraphic unit (such as a formation, member, or bed)

known to contain significant fossils is considered to have a high potential to yield

additional significant fossils. These paleontological resources could be adversely affected

by earth-moving or ground-disturbing activities. The resource could be disturbed or

destroyed. This definition of resource potential or sensitivity differs fundamentally from

that for archaeological resources:

“It is extremely important to distinguish between archaeological and paleontological

resources (see “definitions” section in this document) when discussing the

paleontological potential of rock units. The boundaries of an archaeological resource

site define the areal/geographic extent of an archaeological resource, which is generally

independent from the rock unit on which it sits. However, paleontological sites indicate

that the containing rock unit or formation is fossiliferous. Therefore, the limits of the

entire rock unit, both areal and stratigraphic, define the extent of paleontological

potential” (SVP 2010).

This distinction between archaeological and paleontological sites is important. Most

archaeological sites have a surface expression that determines their geographic location.

Fossils, on the other hand, are an integral component of the rock unit below the ground

surface, and, therefore, are not observable unless exposed by erosion or human activity.

Therefore, a paleontologist cannot know either the quality or quantity of fossils present

before the rock unit is exposed as a result of natural erosion processes or earth-moving

activities. The paleontologist can only make conclusions on sensitivity to impact based

on what fossils have been found in the rock unit in the past, along with a judgment on

whether or not the depositional environment of the sediments that compose the rock unit

was likely to result in the burial and preservation of fossils.

Fossils are seldom uniformly distributed within a rock unit. Most of a rock unit may lack

fossils, but at other locations within the same rock unit concentrations of fossils may



exist. Even within a fossiliferous portion of a rock unit, fossils may occur in local

concentrations. For example, Shipman (1977, 1981) excavated a fossiliferous site using a

three dimensional grid and removed blocks of matrix of a consistent size. The site chosen

was known prior to excavation to be richly fossiliferous, yet only 17% of the excavated

blocks actually contained fossils. These studies demonstrate the physical basis for the

difficulty in predicting the location and quantity of fossils in advance of actual project-

related ground disturbance.

Because it is not possible to determine where fossils are located prior to actually

disturbing a rock unit, monitoring of excavations by an experienced paleontologist during

construction increases the probability that fossils will be discovered and preserved.

Preconstruction mitigation measures such as surface prospecting and collecting will not

prevent adverse impacts on fossils because many sites will be unknown in advance due to

an absence of fossils at the surface.

The non-uniform distribution of fossils within a rock unit is essentially universal and

many paleontological resource assessment and mitigation reports conducted in support of

environmental impact documents and mitigation plan summary reports document similar

findings (e.g., Lander 1989, 1993; Reynolds 1987, 1990; Spencer 1990; Fisk et al. 1994;

and references cited therein). In fact, most fossil sites recorded in reports of impact

mitigation (where construction monitoring has been implemented) had no previous

surface expression. Because the presence or location of fossils within a rock unit cannot

be known without exposure resulting from erosion or excavation under SVP (2010)

standard procedures, an entire rock unit is assigned the same level of sensitivity based on

recorded fossil occurrences.

Using SVP (2010) criteria, the paleontological potential (high, low, undetermined, and

no) of a rock unit is the measure most amenable to assessing the significance of

paleontological resources because the areal distribution of that rock unit can be delineated

on a topographic or geologic map. The paleontological importance of a stratigraphic unit

reflects (1) its potential paleontological productivity (and thus sensitivity) and (2) the

scientific significance of the fossils it has produced. This method of paleontological

resource assessment is the most appropriate because discrete levels of paleontological

importance can be delineated on a topographic or geologic map of the project area.

The potential paleontological productivity of a stratigraphic unit exposed in a project area

is based on the abundance/densities of fossil specimens and/or previously recorded fossil

sites in exposures of the unit in and near a project site. The underlying assumption of this



assessment method is that exposures of a stratigraphic unit in a project site are most

likely to yield fossil remains both in quantity and density similar to those previously

recorded from that stratigraphic unit in and near the project site.

The following tasks were completed to establish the paleontological significance and

potential of each stratigraphic unit exposed in or near the Project site.

The potential paleontological productivity of each rock unit was assessed based

on previously recorded and newly documented fossil sites it contains at or near

the Project site.

The scientific importance of fossil remains recorded from a stratigraphic unit

exposed at or near the Project site was assessed.

The paleontological importance of a rock unit was assessed, based on its

documented or potential fossil content in the area surrounding the Project site.

Chapter 5. Affected Environment



5.1. Geographic Location

The proposed Project is located on SR 101 between PM 35.8 and PM 36.3, where the

highway spans the Smith River in Del Norte County, approximately 9 miles north of

Crescent City, California. The Dr. Fine Bridge is located approximately at latitude

41º52'48.0"N and longitude 124

º08'13.5"W (Figure 2). The Project area is within the

USGS Smith River 7.5-minute (1:24:000 scale) Quadrangle.

Topography of the Project area consists of a river valley incised into an uplifted terrace.

The elevation of the Project area ranges from approximately 20 feet above sea level at the

base of the bridge pier supports to approximately 60 feet above sea level at the top of the

bridge abutments.

5.2. Regional Geologic Setting

The general geology in the vicinity of the proposed Project has been described in some

detail by numerous workers, including Maxson (1933), Back (1957), Blake et al. (1967),

Moore and Silver (1968), Kleist (1974), Kramer (1976), Bachman et al. (1984), Aalto

(1989), Nilsen and Clarke (1989), Polenz and Kelsey (1989), Stanford (1991), and Lock

et al. (2006). Surficial geologic mapping of the Project vicinity has been provided at a

scale of 1:750,000 by Jennings (1977); at a scale of 1:500,000 by Jenkins (1938) and

Irwin (1997); at a scale of 1:250,000 by Wagner and Saucedo (1987); at a scale of

1:100,000 by Delattre and Rosinski (2012); at a scale of 1:62,500 by Back (1957); and at

a scale of 1:24,000 by Davenport (1984). The information in these geologic maps and

published and unpublished reports form the basis of the following discussion. Individual

maps and publications are incorporated into this report and referenced where appropriate.

The aspects of geology pertinent to this report are the types, distribution, and age of

sediments immediately underlying the proposed Project area and their probability of

producing significant fossils during Project excavations.

The Project is located in the northernmost portion of the Coast Ranges Geomorphic

Province and is positioned between the Klamath Mountains Geomorphic Province on the

east and the Pacific Ocean on the west (California Geological Survey 2002). The northern

Coast Ranges consist primarily of Mesozoic volcanics, greywacke sandstone, shale, and

radiolarian cherts that occur as an accretionary prism along the continental margin



(Bailey and Irwin 1959; Blake et al. 1967; Aalto 1989; Jayko and Blake 1989). These

deposits were uplifted and complexly deformed by convergent tectonic processes and

broad wide-scale thrusting (Bachman et al. 1984). Tertiary and Quaternary sediments

overlie wave-cut terraces eroded into the bedrock at the lower elevations (Bachman et al.

1984; Polenz and Kelsey 1998; Lock et al. 2006).

Figure 2. Project location. Scale approximately 1:100,000. Map modified from the USGS 7.5-minute Smith River, High Divide, Crescent City, and Hiouchi Quadrangles.



5.3. Project Geologic Setting

The preserved geologic history in the Project vicinity ranges from Mesozoic to Holocene

and several geologic units are present. For the purposes of this report, these units have

been categorized, from oldest to youngest, as Late Jurassic to Early Cretaceous

sedimentary rocks belonging to the Franciscan Complex, Quaternary stream terrace

deposits, and Holocene fluvial and alluvial deposits (Figure 3). The Franciscan Complex

forms the bedrock and surrounding uplands in the Project area and is unconformably

overlain, in places, by Pleistocene and younger stream terrace deposits and younger

Quaternary sedimentary deposits.

Figure 3. Geologic map of the Project area, modified from Delattre and Rosinski (2012). Scale approximately 1:75,000.

5.3.1. Franciscan Complex (Late Jurassic to Early Cretaceous)

A large portion of the Coast Ranges of California is composed of the Franciscan

Complex and is commonly subdivided into three regions referred to as the Eastern Belt,

Central Belt, and Coastal Belt (Bailey and Irwin 1959, Kleist 1974, Nilsen and Clarke

1989, Stanford 1991). Each belt has been further subdivided into several



tectonostratigraphic terranes (Blake et al. 1982; Aalto 1989; Jayko and Blake 1989). The

Franciscan Complex consists of a wide array of sedimentary, igneous, and metamorphic

rocks, which were emplaced as an accretionary prism along the continental margin.

During and subsequent to emplacement, these rocks were complexly faulted and

deformed by tectonic processes (Bachman et al. 1984).

In the Project area, bedrock consists of a component of the Eastern Belt referred to as the

Yolla Bolly terrane (Blake et al. 1982; Aalto 1989). The Yolla Bolly and other terranes

found in the region, such as the Pickett Peak terrane, have undergone multiple episodes of

deformation (Jayko and Blake 1989) and local outcrops are variably metamorphosed

(Aalto 1989). In the Project area, Aalto (1989) described the local Franciscan as

consisting of intercalated mélange and broken formation units. Delattre and Rosinski

(2012) mapped this area as Eastern Belt broken formation and described this unit as a

broken formation consisting of massive graywackes and interbedded shales, sandstones,

and conglomerates that have been tectonically broken into blocks incorporated into a

fine-grained matrix. Locally, Aalto (1989) described the sedimentary rocks of the

Franciscan as pre-dominantly submarine sediment gravity flow deposits.

The Franciscan Complex as a whole is generally considered to be Mesozoic in age,

although components of the Coastal Belt are now considered to be as young as Miocene

(McLaughlin et al. 1982). The Eastern Belt contains some of the oldest rocks found in the

Franciscan, and the Yolla Bolly terrane has been dated to between the Tithonian (Late

Jurassic) and the Hauterivian (Early Cretaceous) (Aalto 1989).

Franciscan rocks of the Yolla Bolly terrane form the bedrock in the Project area and are

unconformably overlain by Pleistocene terrace deposits or younger sedimentary strata.

During the field survey, outcrops of the Franciscan Complex were observed in and near

to the Project area and typically comprised marine sandstones, greywackes, and shales

(Figure 4).



Figure 4. Franciscan Complex graywacke with intercalated shale. Scale is approximately 4 inches in length.

5.3.2. Quaternary Stream Terrace (Pleistocene to Early Holocene)

Older stream terrace deposits present in the Project area are mapped by Delattre and

Rosinski (2012) as Qt, and as Qpal by Polenz and Kelsey (1998) in the Project vicinity.

Within the Project area, these deposits outcrop and were observed in road cuts at the

north end of the Project during the field survey (Figure 5). These deposits consist of clast-

supported, well-rounded cobbles and gravel within a fine-grained clay-dominated matrix.

Finer-grained facies were also observed in outcrops within the boundaries of the Project.

These facies appear to be devoid of coarser-grained gravels and cobbles. The thickness of

the Quaternary stream terrace deposits is highly variable and has been reported to be over

50 feet in places (Back 1957).



Figure 5. Quaternary Stream terrace deposits. For scale, the post to the base of the stop sign is approximately 7 feet tall.

5.3.3. Quaternary Alluvium and Fluvium (Holocene)

Holocene deposits mapped in the immediate vicinity of the Project area by Delattre and

Rosinski (2012) have been subdivided into four units and include modern stream channel

deposits (Qhc), alluvial deposits (Qha and Qhf), and terraced stream deposits (Qht). The

modern stream channel and terraced stream deposits in the area (Qhc and Qht) consist of

sand, gravel, cobbles, and minor amounts of silt and clay (Figure 6). The clastics present

in these deposits are derived primarily from Franciscan Complex exposures and the

Klamath Mountains. Alluvial deposits in the area form at the base of hillslopes and at

canyon openings and consist of variable amounts of clay, silt, sand, and gravels.



Figure 6. Holocene fluvial deposits in the active Smith River channel overlying Franciscan Complex greywacke which can be seen outcropping at the stream margin.

Chapter 6. Results


Chapter 6. Results

6.1. Geologic Map Inventory and Field Survey

Regional geologic mapping in the vicinity of the proposed Project has been provided by

Jenkins (1938), Back (1957), Jennings (1977), Davenport (1983), Wagner and Saucedo

(1987), Irwin (1997), and Delattre and Rosinski (2012). These geologic maps were

reviewed to determine the stratigraphic units that might be affected by Project-related

excavations. During the field survey for the Project, the geologic maps were ground-

truthed and determined to be reasonably accurate, given the limited exposures and

abundant vegetation cover. Stratigraphy was observed in natural exposures, such as beach

cliffs and stream banks, and artificial exposures, such as road cuts.

6.2. Paleontological Resource Inventory

An inventory of known paleontological resources discovered in the vicinity of the

proposed Project is presented below. Table 1 presents a summary of the geologic units

that may potentially be affected by Project excavations and their respective

paleontological sensitivities. The inventory that follows is based on a review of the

available literature, a search of the UCMP database, and the results of the field survey.

The literature and museum record review conducted for this inventory documented no

previously recorded fossil sites in the limited footprint of the proposed Project.

Table 1. Paleontological Potential of Geological Units Found in the Project Area.

Map Symbol

1 Age Geologic Unit

Lithology Known Paleontological Resources

Paleontological Potential

Qhc, Qha, Qhf, Qht

Holocene Quaternary alluvium and fluvium

Unconsolidated or poorly consolidated gravels and cobbles with minor silt, sand, and clay

No significant resources

Low

Qt Pleistocene to early Holocene

Quaternary Stream terrace deposits

Moderately consolidated gravels, cobbles, and clay with minor silt and sand

No significant resources

Low

KJfbf Mesozoic Franciscan Complex

Graywackes interbedded with shales, sandstones, and conglomerates

Microfossils, rare vertebrates, invertebrates, plants, and ichnofossils

High

1 Map symbols are from Delattre and Rosinski (2012).

Chapter 6. Results


6.2.1. Franciscan Complex

The Franciscan Complex has produced a variety of paleontological resources.

Microfossils have been reported from Franciscan cherts, limestones, and other fine-

grained rocks and have provided important age data (Riedel and Schlocker 1956, Bailey

et al. 1964, Pessagno 1973, Evitt and Pierce 1975, Kramer 1976, Damassa 1979; Sliter

and Silva 1990).

Although the Franciscan Complex is generally poorly fossiliferous with respect to

macrofossils, important fossils have been documented from some localities. Kleist (1974)

reported that plant fragments were common in the upper parts of sandstone beds and also

that burrows were present in isolated sandy and argillaceous beds of the Coastal Belt.

Kramer (1976) also noted that localized shale beds in the Coastal Belt were very rich in

plant fragments. Miller (1986) reported a rich assemblage of trace fossils (feeding traces

and burrows) from the Central Belt. Marine reptiles have been reported from Franciscan

cherts and other deposits. Fragments belonging to two ichthyosaur species (Ichthyosaurus

franciscus and I. californicus) were collected in the 1930s from San Joaquin and

Stanislaus counties (Camp 1942, Bailey et al. 1964, Hilton 2003). The remains of a third

marine reptile (Plesiosaurus hesternus) were collected from San Luis Obispo County

(Hilton 2003). Molluscan fossils, such as ammonites (Mantelliceras sp., Douvilleiceras

sp., and others), the clams Buchia (B. piochii and B.crassicollis) and Inoceramus (I.

labiatus and I. schmidti), and small gastropods (Nerinea sp.), are reported to occur in the

Franciscan (Hertlein 1956, Bailey et al. 1964, Jones 1966, Jones in Armstrong and

Gallagher 1977, Little et al. 1999). Rare occurrences of worm tubes, brachiopods (Little

et al. 1999), and echinoids (Bailey et al. 1964) have also been reported.

Because the Franciscan Complex has yielded vertebrate fossils and invertebrate and

microfossils that have the potential to provide valuable data on the age and depositional

environments of the Franciscan, it is assigned a high potential using both SVP (2010) and

Caltrans (2016) criteria. Any additional fossils discovered in this stratigraphic unit during

Project excavations could be highly significant scientifically.

6.2.2. Quaternary Stream Terrace (Pleistocene to Early Holocene)

Pleistocene sedimentary deposits have produced significant fossils throughout the State

of California (Hay 1927; Jefferson 1991a, b; UCMP online database). Fossils discovered

in terrace deposits can be highly significant in documenting the age of different terrace

levels. These age determinations, in combination with analysis of eustatic and local sea-

level curves, have been instrumental in analysis of regional uplift associated with the

Chapter 6. Results


continental margin and the migration of the Mendocino Triple Junction (Kennedy et al.

1982, Merrits and Bull 1989, Leibson 2004, Lock et al. 2006).

A search of the UCMP online database yielded no Pleistocene vertebrate localities in the

Project area, and no previously unrecorded fossil sites were discovered during the field

survey. However, during the field survey for this Project, PRC paleontologists identified

localities with sediments that appeared conducive to the preservation of fossils.

Because fossils have not previously been reported from this unit, and no previously

unrecorded fossil sites were discovered during the field survey, this unit is assigned a low

potential using both SVP (2010) and Caltrans (2016) criteria.

6.2.3. Quaternary Alluvium and Fluvium (Holocene)

These deposits are too young to produce significant fossil remains (SVP 2010).

Therefore, these deposits are assigned a low potential using both SVP (2010) and

Caltrans criteria (2016).

6.2.4. Summary

The presence of fossils in the Franciscan Complex reported in the literature and museum

records from the region, suggests that there is a high potential for additional similar fossil

remains to be uncovered in this unit. Under both SVP (2010) and Caltrans (2016) criteria,

this geologic unit has a high potential for producing additional paleontological resources.

Identifiable fossil remains discovered during Project construction could represent new

taxa or new fossil records for the Crescent City area and for the State of California. They

could also represent geographic or temporal range extensions. Moreover, additional fossil

remains could make it possible to more accurately determine the age, paleoclimate,

and/or depositional environment of the sediments from which they are discovered.

Finally, fossil remains recovered during Project construction could provide a more

comprehensive documentation of the diversity of animal and plant life that once existed

in Del Norte County and could result in a more accurate reconstruction of the geologic

and paleobiologic history of the California coast during the Mesozoic.

Pleistocene stream terrace sediments occur in the Project area. Although museum record

and literature searches did not yield any previous fossil discoveries from this unit,

sediments conducive to the preservation of fossil remains do occur in this unit on the

Project site. Identifiable fossil remains uncovered during Project excavation activities

could provide important geologic and paleontologic context to this unit, including the age

of deposition, paleoclimate, and tectonic history of the area.

Chapter 7. Environmental Consequences



7.1. Potential Impacts from Project Construction

Geologic units with the potential to contain significant paleontological resources do occur

within the Project area and could be adversely impacted by Project activities. The types

of potential impacts on paleontological resources resulting from Project activities would

involve pile installation, excavations in support of the removal and replacement of the

existing abutments and piers, excavations for drainage diversions and an infiltration

basin, and minor grading to construct access roads. These excavations would be in

Quaternary alluvium and fluvium, Quaternary terrace deposits, or Franciscan Complex at

the north and south approaches to the Dr. Fine Bridge. Activities that occur at the Dr.

Fine Bridge abutments, auguring for piers, and excavations for the detour and Jack-N-

Slide would also have the potential to impact these geologic units. The site-specific

excavations and associated stratigraphic unit(s) that could potentially be affected are

discussed below.

Access and Bridge Approach Road Grading: Ground preparation for the temporary

access roads and the shoulders of SR 101 would involve minor earth disturbance and

would be shallow in depth. At the northeastern end of the Dr. Fine Bridge, Pleistocene

terrace deposits occur at or near the surface and may be affected by even shallow

excavations. The Pleistocene terrace deposits have been assigned a low potential rating

using both SVP (2010) and Caltrans (2016) criteria, which normally would not call for

monitoring. However, due to the fact that the age and depositional environment of these

sediments suggest some potential for significant fossils to be found, emergency discovery

procedures or spot-checking could be implemented if paleontological resources are

encountered (Chapter 8, Recommended Monitoring, Collection, and Treatment

Measures).

Infiltration Basin: Excavation for an infiltration basin will involve shallow excavations

in the Quaternary alluvium and fluvium located in the northwest Project area. Because

this geologic unit has a low potential rating, no monitoring for paleontological resources

would be required.

Pile Installation: Piles will be required for bridge abutment support, detour bridge

support, and the Jack-N-Slide apparatus. These piles would affect sediments of the

Quaternary alluvium and fluvium and Franciscan Complex. These activities could

adversely affect significant paleontological resources in the Franciscan Complex.



However, each pile is expected to be driven into place via vibratory or impact hammers.

This method of installation would not produce salvageable fossil material. Therefore, pile

installation would not need to be monitored.

Pier Installation: New piers would be required for bridge support. Excavations for pier

installation would affect sediments of the Quaternary alluvium and fluvium and the

Franciscan Complex. The piers would be installed with a variety of methods. Those

methods that bring sediments of the Franciscan Complex to the surface as spoils (e.g.,

augering or the use of a drilling bucket) would need to be monitored (Chapter 8,

Recommended Monitoring, Collection, and Treatment Measures).

Abutment Construction: Excavation in support of removal of the existing abutments

and their replacement with new structures would affect the Pleistocene terrace deposits or

the Quaternary alluvium and fluvium and the Franciscan Complex. Where these activities

penetrate through the overlying Pleistocene terrace deposits or Quaternary alluvium and

fluvium and into the Franciscan Complex, these activities would need to be monitored.

Additionally, excavations in the Pleistocene terrace deposits located at the north abutment

should either employ spot-checking or have emergency discovery procedures in place

(Chapter 8, Recommended Monitoring, Collection, and Treatment Measures).

7.2. Cumulative Impacts

The potential cumulative impacts on paleontological resources resulting from Project

construction are unknown since most past projects in the Project vicinity did not consider

impacts to paleontological resources and no monitoring or collection of paleontological

resources took place. In addition, given the rural and undeveloped nature of the Project

area and the relatively few past projects with major earth-disturbance, it is difficult to

judge if past projects had any impact on significant paleontological resources. We know

of no present projects that could be having an adverse impact on paleontological

resources. As discussed above, the Dr. Fine Bridge Project could result in direct and/or

indirect impacts. However, this Project is not likely to contribute any cumulative effects

because the monitoring and collection of paleontological resources described in Chapter

8, Recommended Monitoring, Collection, and Treatment Measures, will be implemented

and any resources encountered would be recovered and managed appropriately. Likewise,

any reasonably foreseeable future projects that would be located in the vicinity of the Dr.

Fine Bridge Project potentially could result in adverse impacts on paleontological

resources. However, implementing similar measures required by the Paleontological

Resource Preservation Act on U.S. Forest Service lands and required by the Caltrans SER

on highway construction projects would again result in reduced-impacts.

Chapter 8. Recommended Mitigation Measures


Chapter 8. Proposed Monitoring, Collection, and Treatment Measures

This section describes proposed monitoring, collection, and treatment measures that

would be implemented to reduce potential adverse impacts to paleontological resources

resulting from Project construction. Implementing monitoring, collection, and treatment

measures are necessary because of the potential for adverse impacts on paleontological

resources within the Franciscan Complex and Pleistocene terrace deposits during some

Project construction activities. The monitoring, collection, and treatment measures

proposed are consistent with Caltrans SER (2016) criteria and with SVP standard

procedures for mitigating adverse construction-related impacts on paleontological

resources (SVP 1996; 2010).

8.1. Retain a Professional Paleontologist and Prepare a PMP

Prior to construction, a qualified professional paleontologist shall be retained to both

design a paleontological mitigation program (PMP) and implement the program during

all project-related ground disturbance. The PMP shall include preconstruction

coordination; construction monitoring during activities identified within this report;

emergency discovery procedures during excavation; sampling and data recovery, if

needed; preparation, identification, and analysis of the fossil specimens salvaged, if any;

museum storage of any specimens and data recovered; and preparation of a detailed

report of the resources recovered. Prior to the start of construction, the qualified

professional paleontologist shall conduct a detailed field survey of each exposure of

sensitive stratigraphic units in the construction right-of-way that would be disturbed.

Earth-moving construction activities shall be monitored wherever these activities have

the potential to disturb previously undisturbed strata with high sensitivity. Emergency

discovery procedures and/or spot-checking would be employed in excavations in the

Pleistocene terrace deposits. Monitoring will not need to be conducted in areas where

sediments have been previously disturbed or in areas where exposed sediments will be

buried, but not otherwise disturbed.

8.2. Provide Worker Education on Paleontological Resources

Prior to the start of construction, project managers and all construction personnel

involved with earth-moving activities would be informed that fossils could be discovered

during excavating, that these fossils are protected by laws, on the appearance of typical

fossils that might be discovered in the area, and on proper notification procedures. This

Chapter 8. Recommended Mitigation Measures


worker training would be prepared and presented by a qualified professional

paleontologist.

8.3. Result of Implementation

Implementation of these monitoring, collection, and treatment measures will allow for the

recovery of fossil remains and associated specimen data and corresponding geologic and

geographic site data that otherwise might be lost to earth-moving and to unauthorized

fossil collecting. With a well-designed and implemented PMP, Project construction could

result in beneficial impacts on paleontological resources through the discovery of fossil

remains that would not have been discovered without Project construction and, therefore,

would not have been available for scientific study. The recovery of such fossil remains as

part of Project construction could help answer important questions regarding the

geographic distribution, stratigraphic position, and age of fossiliferous sediments in the

Project area.

Chapter 9. References



Aalto, K.R., 1989, Franciscan Complex geology of the Crescent City area, northern

California: p. 21-46 in Aalto, K.R., Harper, G.D., Carver, G.A., Cashman, S.M.,

Miller, W.C., and Kelsey, H.M., Geologic evolution of the northernmost Coast

Ranges and western Klamath Mountains, California: Galice, Oregon to Eureka,

California July 20-28, 1989, Field Trip Guidebook T308American Geophysical

Union, Washington, D.C., 82 p.

Armstrong, C.F., and Gallagher, K., 1977, Fossils from the Franciscan assemblage,

Alcatraz Island: California Geology, vol. 30, p. 134-135.

Bachman, S.B., Underwood, M.B., and Menack, J.S., 1984, Cenozoic evolution of

coastal northern California: p. 55-66 in Crouch, J.K., and Bachman, S.B. (editors),

Tectonics and sedimentation along the California margin, Pacific Section SEPM

vol., 38, 188 p.

Back, W., 1957, Geology and ground-water features of the Smith River plain, Del Norte

County, California: U.S. Geological Survey Water-Supply Paper, 1254, 76 p.,

(incl. geologic map, scale 1:62,500).

Bailey, E.H., and Irwin, W.P., 1959, K-feldspar content of Jurassic and Cretaceous

graywackes of the northern Coast Ranges and Sacramento Valley, California:

American Association of Petroleum Geologists Bulletin, vol. 43, no. 12, p. 2797-

2809.

Bailey, E.H., Irwin, W.P., and Jones, P.L., 1964, Franciscan and related rocks and their

significance in the geology of western California: California Division of Mines

and Geology Bulletin 183, 177 p.

Blake, Jr., M.C., Irwin, W.P., and Coleman, R.G., 1967, Upside-down zonation,

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Appendix A. Standard Procedures for the Assessment and Mitigation of Adverse Impacts to Paleontolgical Resources


Appendix A. Standard Procedures for the Assessment and Mitigation of Adverse Impacts to Paleontological Resources

Appendix B. Conditions Of Receivership For Paleontological Salvage Collections


APPENDIX B. Conditions of Receivership for Paleontological Salvage Collections



CONDITIONS OF RECEIVERSHIP FOR PALEONTOLOGIC

SALVAGE COLLECTIONS

Society of Vertebrate Paleontology

Conformable Impact Mitigation Guidelines Committee

Robert E. Reynolds, Chairman

Society of Vertebrate Paleontology News Bulletin Number 166, pages 31-32

February 1996

1. The repository museum and its curator maintain the right to accept or refuse the

materials.

2. The materials received must fit with the repository museum's mission and policy

statements.

3. All repository arrangements must be made with the curator in advance of receipt. All

arrangements for inventory numbers and locality numbers must be made in advance.

"Museums are not a dumping ground."

4. The museum will act as the trustee for the specimens. A deed of gift from the land

owner or agent must be provided. A loan form or Memorandum of Understanding must

be prepared for specimens from government lands.

5. Specimens must receive discrete locality numbers. Locality data must be to the

maximum specificity available and plotted on 7.5-minute topographic maps, and as

specific as allowed by stratigraphic collecting and field mapping. The repository may

require the repositor to bear the cost of entering locality data into computerized data files.

6. All reports prepared to meet mitigation requirements, field notes, and photographs

must be provided at the time of transfer to the repository museum.

7. Specimens must be delivered to the repository fully prepared and stabilized.

Standards of stabilization and modern conservation techniques must be established prior

to preparation and must be acceptable to the repository institution. Details of stabilizing

materials and chemicals must be provided by the repositor. For microvertebrates, this

means sorting and mounting. For large specimens, including whales, this means removal

of all unnecessary materials and full stabilization. Fossiliferous matrix must be washed

and processed. Earthquake-proofing includes inventory numbers on corks and in vials. In

storage, specimens must be insulated or cushioned to protect each from contact or



abrasion. Oversized specimens must be stored on shelves or on racks developed to fit

existing constraints of the repository museum. The repositor must provide for all

nonstandard materials for storage.

8. Specimens must be individually inventoried in accordance with the established

system at the repository museum. The specimen inventory must be acceptable to and

meet the requirements of the lead agency. Specimens must be identified to element and to

maximum reasonable taxonomic specificity. Batch or bulk cataloging must be avoided.

9. Specimens must be cataloged in accord with the repository system so that specimens

are retrievable to curators and to researchers. The repository museum may require that the

repositor bear the cost of having repository staff catalog specimens into computerized

data bases.

10. The repository may require the repositor to bear the cost for completing preparation

and stabilization, completing inventory, and completing cataloging.

11. There will be a one-time fee charged by the repository for permanent storage of

specimens. This fee will be utilized to compensate the repository for storage space,

cabinets or shelves, access or aisle space, a retrievable catalog system, additional

preparation, specimen filing, and labor involved in the above. The repository reserves the

right to charge the repositor for unpacking and placement of specimens in approved

storage cabinets.

© 1996, The Society of Vertebrate Paleontology

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