INFUSORIA. 
49 
4. Not one of the American infusorial deposits is, in its elementary forms, similar to those 
which form the chalk marl in the south of Europe; nevertheless there is found in the 
deposit near Spencer in Massachusetts, the Rotalia globulosa, which is decidedly 
peculiar to the writing chalk.* 
5. The greater part of the fossil deposits in North America occur under peat banks, and 
belong also, by their elementary forms, clearly to the brackish fresh water forms of the 
sea coast, although some of them lie a long way from the sea coast.f 
6. It is remarkable that as far as these observations extend upon the earth, the very peculiarly 
formed many-toothed, diadem, and saw-shaped Eunotia are met with only in the United 
States, Sweden and Finland, and no where living.^ On the contrary, the Spongia phil- 
lipensis is observed only in Lucon and Eastern North America, both in fossil deposits; 
these places differing as much in climate, as the former correspond. 
7. The following is Ehrenberg’s catalogue of American Bacillaria, Polythalamia, &c.: 
A. Fossil. 
Amphiphora navicularis. 
Gomphonema nasutum. 
Navicula oblonga. 
Cocconema arcus. 
—- 
undulattun. 
— porrecta. 
— lunula. 
Hemantidium gracile. 
— pumilis. 
Eunotia amphioxys. 
Navicula americana. 
— silicula. 
— biceps. 
— 
amphigomphus. 
— sillimanorum. 
— bidens. 
— 
amphioxys. 
— tumidula. 
— monodon. 
— 
bacterium. 
Tabellaria amphilepta. 
— prserupta. 
— 
baileyi. 
— nodosa. 
— uncinata. 
— 
costata. 
— biceps. 
— zebrina. 
— 
decora. 
Spongia ramosa. 
Fragillaria constricta. 
— 
dilatata. 
— serpentina. 
— pinnata. 
— 
grammatostoma. 
— setosa. 
— paradoxa. 
— 
hitchcockii. 
Thylacium ossiculum. 
Gomphonema americana. 
— 
legumen. 
— semiorbiculi 
lanceolatum. 
* The statements of Ehrenberg in this paragraph contain two errors, which he had not the means of correcting: 
1. The infusorial deposit of the tertiary of Virginia, I have shown to contain all the predominant siliceous forms of the chalk marls 
of Oran, Caltasinelta, etc.; forms which I have also recently detected living, both at Boston harbor and in the Hudson at 
West-Point. 
2. The Rotalia globulosa, found by Ehrenberg in the siliceous marl from Spencer, Massachusetts, must have been introduced 
accidental!) from a particle of chalk, or from the use of impure Canada balsam which had been used in examining chalk. I 
can confidently assert that neither Rotalia globulosa, or any other calcareous polythalamian form, occurs in any of our bog 
deposits of infusoria. J. W. B. 
11 have seen all the principal forms, in a living state, as far west as Ouisconsin river near Fort Winnebago, and therefore 
cannot consider brackish water as at all necessary to their existence. J. W. B. 
t These all occur in a living state at West-Point. J. W. B. 
Geol. isT Dist. 7 
