I o Bulletin of the Natural History Society. 
which they are ornamented, are very striking objects under the 
microscope. In the fossil condition these seeds are generally black, 
with a smooth shining surface, and the keels are usually coated with 
shining white crystals of calcareous salts. In the washings of the 
marl and clay beds these minute seeds float to the sides of the vessel 
and may be removed in great numbers. The seeds or spores though 
comparatively scarce in the low*er divisions of the deposit, become 
very numerous in Div. No. 6, and in Nos. 7, 8 and 9 they are found 
in enormous numbers. They appear to be most numerous in the 
middle portion of Nos. 7 and 8, respectively, and in the upper part of 
No. 9. The species are distinguished by the form and size of the 
spores, the number and distinctness of the stride or keels, &c. 
Dr. Allen finds the spores of one species, which he identifies with 
Chara coronata^ Ziz., as low down as the lower half of No. \h — the 
very beginning of the fresh-water clay. This species I found to 
increase in number in the upper part of No. 1, and the lower part 
of No. 2, but in the upper 'two thirds of No. 2, and in the lower 
half of No. 3, it appears to be scarce, as none were observed. It 
reappears in considerable numbers in No. 4 and the lower third of 
No. 5. This is the limit of the clayey sediment in the deposit, and 
I did not detect it higher up. Dr. Allen, however, found examples 
of what he considers the same species, “ though sparingly,” in the 
higher numbers, 6, 7, 8 and 9. The species has left its remains most 
abundantly in the lacustrine clay, and they are especially numerous 
in those parts of the clay beds which are most heavily charged with 
mineral matter of sedimentary origin. Its abundance in these beds 
would seem to indicate that the species is partial to waters contain- 
ing an abundance of argillaceous sediment. In the accompanying 
wood cuts the first four figures, copied from drawings by Dr. Allen? 
represent examples of this form of nucleus, arranged from left to 
right as they are found at successively higher levels in the deposit : 
the two last figures of the second row represent irregular forms, or 
varieties of the same species. 
Another species which Dr. Allen detected in samples from the 
lower part of the lacustrine deposit is of small size, nearly globular, 
and has from 6 to 7 keels. This nucleus was found in the lower 
part of 26 and of 36 ; also in 4a and in 66, &c. Its range was 
therefore much the same as that of the last named species. Dr. 
