NOTES ON NEW AMERICAN SPECIES AND LOCALITIES 



MICEOSCOriC ORGANISMS 



I. 



Fossil Marine Diatomaceae in California. 



In examining, at the request of Dr. J. R. Chilton, of New York, some specimens 

 of earthy minerals which were collected in California by Washington Chilton, Esq., 

 I found one highly interesting specimen resembling a white clay, which the micro- 

 scope proved to be almost entirely composed of fossil marine species of Diatoma- 

 ceae. 



The specimen was from Suisiui Bay, twenty-five or thirty miles above San Fran- 

 cisco, California, where Mr. Chilton says a large deposit of a similar character occurs. 

 This is the first locality of fossil marine Dlatomaccae which has been detected on 

 the Pacific side of this Continent. It abounds in numerous species of Cosciitodisci, 

 Acdnoajcli, Actinoptyvhi, Mustogonia, &c. which I cannot distinguish from the com- 

 mon species in the "infusorial strata" of Maryland and Virginia. 



The predominant species, however, which forms a large portion of the mass, is a 

 minute silicious shell which I believe to be undescribed, and which appears most 

 nearly allied to some of the species of Kiitzing s genus Dentimla; I shall refer to it 

 as Denticula laula, B. (See Plate, Figs. 1, 2, and description, page 9.) Among 

 the other species from this locality I recognized the following, which also occur 

 fossil at Richmond, Virginia, viz : Coscinodisms radiatus, C. Uneatus, C. ocidus-irklis, 

 G. gemmifer, Pyxldicula cruciata, and Dichjoclm fihula of Ehrenberg, while no trace 

 was found of other characteristic forms of the Virginian deposits, such as the Gul- 

 lioneUa sulcata, Zijgoceros rhowbus, Dentlcella tridentata, Goniolhecium liogersii, 

 Eupodisei, &c. of Ehrenberg. The Californiau deposit also appears to be entirely 

 free from any Polythalaraian shells. 



Should this notice meet the eye of any scientific traveller in California, it may 

 induce him to furnish further infurmation concerning the geological relations of this 

 interesting deposit, and to collect a good supply of specimens for a more complete 

 study. 



