? "ee 
Fig. 9, 10. Actinocyclus. Fossil at Richmond, Va. 
Fig. 11. a,b. Actinocyclus.. a, base ; 0; side view, showing the al- 
ternate elevations and depressions which cause the light and dark por- 
tions seen on a. Fossil at Richmond. 
Fig. 12. Coscinodiscus lineatus. Fossil in tertiary infusorial. strata 
of Virginia, at Richmond, and on Rappahannock River. — 
Fig. 13. Coscinodiscus patina. With the preceding. 
. Fig. 14, Coscinodiscus radiatus. With the preceding. 
Fig. 15. Scale representing 31°,;ths of a millimetre, “magnified 
equally with the sketches. 
Fig. 16. a, 6. Navicula ihe recent and fossil, fluviatile, ¢, , ey o 
the orifices. 
Fig. 17. a, 6. Navicula viridis, copied from Ehrenberg. See page 97. 
Fig. 18. Navicula 5 marine, at pinaEwa, Conn. 
Fig. 19. Navicula , marine, with t ing. 
Fig. 20. Navicula ——, fluviatile, West Point, &c. 
Fig. 21. a, b. Biililniee: striatula, fluviatile, recent and fossil. 
Fig. 22. Navicula ——, fossil at Richmond, Va 
Fig. 23. a, b. Navicula ——, fluviatile, recent and fossil. 
Fig. 24. a, &. Navicula sigma? marine, Stonington. 
Fig. 25. a,b, Navicula , fossil at Richmond, Va. 
_ Fig. e a, b, c. Eunotia arcus, fluyiatile, recent and fossil. _c, cross 
* 
Section. 
Fig. 27 - a, ©. e. Eunotia —, brackish ditches, N. Jersey. Cc, cross 
28. Eunotia monodon, ‘a é 
. 29. Eunotia diodon, | 
Fig. 30. Eunotia cose 
Fig. 31. Eunotia tetraodon, 
Fig. 32. Eunotia eee 
Fig. 33. Eunotia serra, 
Fig. 34. Cocconeis , marine, Florida. 
, Pig. 35. Bacillaria paradoxa, ta Hudson river. 
Fig. 36. a, b. Bacillaria tabellar ere recent 
Fig. 37. a, b. Bacillaria gbotane full grown ? and fossil. 
Fig, 38. Bacillaria , marine, at Stonington, Conn. Recent. 
Fig. 89. Tessella catena? marine, at Stonington, Conn. Recent. 
Fig. 40. Fragillaria pectinalis, 
Fig. 41. Fragillaria bipunctata ? 
Fig. 42. a,b. Meridion vernale, fluviatile, recent, and fossil in fragments. 
‘Vol. xin, No, 1.—Oct.—Dec. 1841. 14 
fluviatile, recent and fossil. 
> fluviatile, recent and fossil. 
