310 Notice of Ehrenberg’s Memoir on Microscopie Life. 
< 
southern end of South America to the polar extremity of North Amer- 
ica, or through a range of more than 50° south to 60° north latitude. 
*Cocconeis placentula. *Gomphonema clavatum. 
sean Scutellum. ye minutissimum. 
*Eunotia amphyoxys. -*Pinnularia viridis. 
5 iceps. _ *StaurSptera aspera. 
* aba  *Spongiolithis acicularis. 
*Fragillaria rhabdosoma. 
Those distinguished with a * are found agreeing in characters in ™ 
Central America and in Europe. 
8. Six species are distinguished from all the others by the peculiarity 
of their forms, and are placed under the genera Climacosphenia, 
niothecium, Podosira, Rhizosolenia, Sphenosira and Terpsinoé, 
e music animalcule, Terpsinoé musica, which resembles a printed 
sheet of music with twelve notes, standing by sixes in two rows, is re- 
markably distinct from any European form. 
In America asin Europe, there occur not merely untraceable, 
transient, momentary appearances of the minutest forms of life, but 
also wide-spread fossil strata of their easily recognizable remains, whi 
form earthy and even rocky masses. 
10. The only American microscopic organisms which form earth 
and rocks, are, as in Europe, the siliceous infusoria or the calcareous 
Polythalamia. 
. There occur in North America (Andover, Wrentham, Mass.) 
fossil beds of siliceous earth, which are to a considerable extent com- / 
posed of loricated monads, (Trachelomonas,) and not formed as usual 
merely of Bacillaria and Phytolitharia. Iron ochre occurs also in Mas 
sachusetts, which is very similar to the Gallionella deposits. 
12. Beds of minute fossil siliceous organisms have been observed of 
the thickness of fifteen feet at Andover, and twenty eight feet at Rich- 
mond. Similar beds occur by the Amazon in South America, and in 
great extent from Virginia to Labrador. 
13. The relations of the invisible, calcareous Polythalamia are also 
the same in America as in Europe; indeed, the first short examination 
alone has proved their gigantic development. They may be distinctly 
recognized as forming the firm earth and the rocks of central North 
America, as a cretaceous formation from New Jersey to the sources of 
the Mississippi near the Rocky Mountains.* Eyen the Andes of the 
ose who are not familiar with American geology should bear in mind that 
the cretaceous formation only exists as a narrow belt along the Atlantic slope, 
skirting the older formations which occu y the greater portion of the United 
States, and that it is chiefly in the far west that it has the gigantic development —— 
alluded to by Ehrenberg. 
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