I 



The exaniination of certain Infusorial 

 earths or clays for the United States Geological Survey. j 



By ARTHUR M. EDWARDS, M. D. 



On the 3oth. of May 1891 I received certain Infusorial earths 1 

 containing Bacillaria, called Diatomaceas, from the Smithsonian In- j 

 stitution in Washington, D. C. which 1 understood were sent me 1 

 by the United States Geological Survey. They were interesting to \ 

 the student of the Bacillaria and doubly interesting too being from 1 

 the Great Plain of Fremont in Utah, Nevada and California and j 

 which I subsequently called the Occidental Sea. I was to examine 

 them and thereafter report thereon. The report was held off until • 

 now. 



The Plain was called the Occidental Sea which I surmised was i 

 formed in the Eocene Period or Cretaceous Period. My reasons \ 

 for placing it there it is not necessary to state now as that is geo- ' 

 logiccil and this report is microscopica! or microgeological. It is a | 

 tract of country covering a space much larger than any modem I 

 Sea if \ve except the Pacific perhaps. ; 



1 will describe microscopically what I found in these speci- 



mens. Thereafter I must be permitted to sav somcthing about the | 



1 

 Occidental Sea geologically. ' 



They are first: 



Beaver Lake beds, Beaver Valley, Nevada. j 



A clayey substance containing " 



Ampbora ovalis, F. T. K. - '■ 



Coccofieis place?ilnla, C. G. E, ' 



