MICROSCOPIC FOSSILS FROM THE CHALK OF SWANSCOMBE. 369

on to Greenhithe, some returning at once to London, othersremaining for tea. It was explained that although the chalk hereabounds with fossils, the collaboration of the workmen is neces­sary for the acquisition of any considerable collection.

Appended is a report by Mr. Frederick Chapman on themicroscopic fossils found in some chalk obtained from theSwanscombe pit.

NOTE ON SOME MICROSCOPIC FOSSILSFROM THE CHALK OF SWANSCOMBE.

By FREDERICK CHAPMAN, F.R.M.S.

DU R ING the excursion made by the members of the Geolo­gists' Association to the above place on June r Sth, 1894',

a small specimen of chalk was taken, with the view of testing itfor microscopic fossils.

The sample was obtained from the zone of Micrasters, pro­bably the lower portion, or zone of Micrasler cor-testudinarium.The particular pit from whence the specimen came was the lastone visited, and the section of chalk here showed very strikinglythe peculiar intercalation, along the planes of bedding, of " somelayers of brown sandy clay, sometimes eight inches thick, in partsrather finely bedded," as recorded by Mr. Whitaker;" in a Chalk­pit about one mile S.S.E. of Stone, and which, as he remarks,have evidently been washed down from the overlying beds, throughrifts in the Chalk.

Taking into consideration the small quantity of Chalk exa­mined (about two cubic inches), the results, especially as regardsthe Ostracoda, are particularly satisfactory.

There are twenty-six species and varieties of the Ostracoda,one of which, viz., Cylheropteron laticristatum (Bosquet), is newto British Cretaceous deposits; and amongst the number are twoundetermined species of Cythereis.

Of the Foraminifera there are forty-eight species and varieties.It is a fact worth recording that the inornate species of Globigerinaare here conspicuous by their almost complete absence, beingrepresented by a solitary specimen of G. bulloides, d'Orbigny,whilst G. marginata, Reuss - the prickly-margined species-iscommon. The occurrence of the siphonate form of Tritaxia,T. foueolata, Marsson, is also interesting, as it is apparentlyconfined to the Upper Chalk; and I take this present opportunityof mentioning its occurrence, with the type species T. tricarinata,Reuss, in the Phosphatic Chalk of Taplow, since it was inad­vertently omitted from my list. t

• Mem. Geol. Survey; Geology ofLondon, 1889, vol. i, p. 82, fig. 5.f Quart. f ourn; Geol. Soc., vol. xlviii (1892), p. 516.

NOVEMBER, 1894.

370 MICROSCOPIC FOSSILS FROM THE CHALK OF SWANSCOMBE.

In the list given below, initial references are made as tofrequency of occurrence, viz., very rare; rare; frequent; common ;and very common.

Os t racoda.

I. Pontocypris tr iqnetra (J ones) u.r. 16. C)' lheropleron laticristatum,2.

""'igonalis, J. & H. •'.1'. (B osquet) o.r

3· B air dta Harris iana; Jones . t '.Y. 17. "sphenoides ( Reuss.) r .

4· "var, 18.

"concentr icum

amplior, r. & H . r. ( Reuss), va r, 1/il'ginea,5· "

subdeltoidea ( 1\1 iinster) r, J ones . . c.6, B).thoc),pris B roumei, J . & H. r . 19· "

umbonatum (Will.)7. "

silicula (J ones), var. acanthopteravaT. minor, J . & H . r : (Marsson) r,

8. ( VlheYeis ornatissima (Reuss.) I 20. Cythe,'ella ouata ( Rom er) v.c.I) .

" "var, 21. Muens leri ( RUmer) c,

reticulata, J. & H . f. 22 . subreniformis,] .&H. r,

10." "

var, 23· obouata, J. & H . ;:nuda, J. & H . r, 24· "

p':,JliamsonianaII.

" "var. Jones f·

striata , J. & H. u.r , 25· " "var,

12."

W 1'1ghtii , J . & H . u,r: granulosa, Jones l-13· sp. indet, V . I'. 26.

" "var,

14· "sp, indet. 'ZJ .r . striata, J. & H. r.

IS· Pseudocythere (?) SImple x, J .&H. I-

Foraminifera.

I. Textu lar ia glohulosa, Eh renb . I 26 . Nodosaria ooli'lua (L.) u.r -2.

"turris, d'Orb, r, 27. " Z ippei, Reu ss. o.r.

3· "sagit/ula, Defr. r , 28. Frondicular ia angustissima,

4· Vern euil ina triquetra( Munst.) r, Reuss. . V. T.

5· " spin ulosa, Reuss.. I- 29· Vaginulina legumen (L. ) V ,Y.

6. Tritaxia foueolata , Marsson f 30. Cristellar ia cultrata (M ontf.) c.7· "

tr tcar inata, Reuss. V . I". 31. "rotu lata (Larn .) . I

8. ( ?) Spiroplecta annectens (P. 32. naoicula, d'O rb. . V . I ',

& J .) . . v r . 33· "Gau d':rana,d'Orb. r.

9· Gaudryina :Jonesiana , W right o.r. 34· "crepidula (F .&M.) u.r ,

10. " pup oidtS,d'Orbigny v .r. 35. F labdlina Baudouiniana ,II. Bulim ina elegan s, d 'Orb. r, d'Orb, . . . r.12.

"obtusa, d 'Orb. f. 36.

"rugosa, d'Orb. r ,

13· "1m-vis, d'Orb. r , 37. " pulehr,r, d'Orb. • V .Y .

14· " Murehisoniana, 38. Ramulina globulifera, Brady . r;

d'Orb• • r . 39· Globigerinamarg" ,ata(Reuss.) c.15· 1Jar iabzJis, d'O rb. f · 40. " bulloides, d'Orb. tr.r16.

"obliqua, d 'Orb, V.I' . 41. Truncatulina Ungeria na

17. "Presli, Reuss. V .I' . (d'Orb.) . I

18."

elegans, d'Orb, new 42• Anomalina ammonoidesvar, ? . . . V. 1·, ( Re uss.) e.

19· Virgulina Schreibersiana, 43· "Lorneiana (d 'Orb.) c.

Czjzek. . . r , 44· ,. rotula. d'Orb. r ,20. Bolivina obsoieta , Eley, = B . 45· Pulvinulina Michelin iana

'1uadrilatera (Schw. ) • c. (d'Orb.) c21. Lagena sulcate, W , & J . r , 46. "

repanda (F. & M.). v r,22.

"gracilis, Will. v. r . 47· " "

var,23· NOdosaria aculeaia; d 'Orb. r, concamerata (Mont .) V .1' ,

24· "oligostegia, R euss. . r , 48. R otalia Soldan ii, d'Or b. I

25· "ronsobrina (d 'Orb.) V ,Y . 49· "

exsculpta, Reuss. I