394 Miscellanies, 



infusoria, sent for his examination by Professors Silliman, Bailey and 

 Hitchcock. The chief results of his examinations of American species 

 are — 



1. In North and South America, there occur not only living but fos- 

 sil microscopic organisms, forming strata geologically important, and ve- 

 ry similar in their relations to the European. 



2. The American forms are for the most part similar to the Euro- 

 pean. 



3. One hundred and forty-three species are common to Europe, and 

 seventy-one, or one third, peculiar to America. 



4. Not one of the American infusorial deposits resembles in its ele- 

 mentary forms the chalk marl of the south of Europe. Nevertheless 

 there is found in the deposit near Spencer, Mass. the Rotalia glohulosa, 

 which is decidedly peculiar to the writing chalk. 



(This statement of Ehrenberg was made before he was aware of the 

 discovery made by Prof W. B. Rogers of the tertiary infusorial strata 

 in Virginia. I have shown these strata to agree with those of Oran, &c. 

 in containing immense numbers of the same species of Actinocyclus, 

 Coscinodiscus, Dictyocha, &c. which characterize the chalk marls of 

 Oran, Caltasinetta, &c. Some of these species I have seen still living 

 in our waters, not only on the sea-shore, as at Boston harbor, but also 

 sixty miles up the Hudson river. 



The occurrence of the marine Rotalia glolulosa in the infusorial de- 

 posit of Spencer, an inland town of Massachusetts, would lead to curi- 

 ous inferences were the fact well established ; but having repeatedly 

 examined specimens from that locality, and never having seen in them 

 any but fluviatile organisms, I am inclined to think that a portion of 

 chalk may have been accidentally mixed with Ehrenberg's speci- 

 mens.— J. W. B.) 



5. Most of the fossil deposits in North America are found in peat bogs, 

 and contain forms of infusoria clearly referable to the brackish fresh-wa- 

 ter forms of the sea coast, although some of them are at a great distance 

 from the sea. 



(I found some of the most common fossil species, still living, as far 

 west as Ouisconsin river. — J. W. B.) 



6. Catalogue of American infusoria determined by Ehrenberg : 



A. Fossil. 

 Amphiphora navicularis 

 Cocconema Arcus 

 " lunula 



Eunotia amphioxus 

 " biceps 

 " bidens 



Eunotia Monodon 

 " prserupta 

 " uncinata 

 " zebrina 

 Fragillaria constructa 

 " pinnata 



" paradoxa 



