J. W. Bailey on New Localities of Fossil Diatomacee. 179 
Arr. XV.—On some New Localities of Fossil Diatomacee in 
California and Oregon ; by Prof. J. W. Bamey, West Point, 
New York.’ 
Some interesting specimens of fossil Diatomacez from Califor- 
nia and Oregon having come into my possession, I am induced to 
publish the following brief notices of them, in hopes to direct 
the attention of travellers in those regions to those remarkable 
deposits, and thus acquire more information concerning their po- 
sition and extent. 
he first specimen of fossil Diatomacew from California, I 
found among specimens of minerals collected two or three years 
ago in California by Washington Chilton, Esq., of New York. 
It was from Suisun Bay, 25 to 30 miles above St. Francisco, 
where Mr. Chilton says a large bed of similar material exists. It - 
consists of a light white claylike substance made up entirely of 
2. In a box of minerals collected in Oregon and California by 
Lt. Robt. Williamson, of the U. 8. Topographical Engineers, I 
a8 specimens A, B, C, and D. 
Specimen A.—This is a very light white substance, made u 
of the siliceous shells of fluviatile Diatoms. The predominant 
Species are a small Gallionella, and a Discoplea mingled with a 
few species of Epithemia, Cocconema, Gomphonema and Spongi- 
Olites. "This specimen was without a label, but is believed to be 
the specimen referred to in the following extract from a letter re- 
ceived from Lt. Williamson; “You will find some of the light 
White clay from Pit River, which I spoke of to you.” ‘This is, 
T believe, the same substance which has given rise to the news- 
Paper accounts of cliffs in California composed of carbonate of 
Magnesia, 
’ Specimen B.—This is a light white chalky mass, whose local- 
tty is not given. It consists of fluviatile species, among which 
Various species of Biblarium are quite abundant. The species 
of this genus have been found living in Siberia, and fossil in 
gon. Lt. Williamson’s specimen resembles the Oregon mass 
Paed by the U. S. Exploring Expedition under Capt. Wilkes, 
Pie pe a different group of forms and therefore must be 
& different locality. : 
