110 Wisconsin Academy of Sciences, Arts, and Letters. 
0. G. E., which is common—in fact, is the prevailing form of 
the Occidental Sea,. See American Journal of Science, 1891. 
“Mixed with these forms, although in small quantity, are 
the following: Navicula appendiculata (C. A. A.) ; N. ob- 
longa (F. T. K.), and Nitzschia scalaris (C G. E.) This last 
is common in the brackish water of our coast. It is also seen 
in the Glacial period clay, which is fresh-water. 
“There is also present a form which looks like Mastogloia 
lanceolata (C. K. T.). 
“When we consider the origin of this ‘diatom-earth/ there 
are present mostly fresh-water forms; hut one form is decidedly 
marine, as bacillaria grow now, and has not as yet been de¬ 
tected living in fresh water. This is what has been called 
Uyalodiscus FranMinii (0. G. E.), and was orginally found 
in the waters of the frozen Forth, but is common now every¬ 
where. It is also called Uyalodiscus subtilis (J. W. B.), and 
is proposed by Bailey to be used as a Test’ for microscopic ob¬ 
jects. But it is also found in the mud of a brackish-water 
swamp at Melbourne, Australia,, and perhaps was washed down 
from fresh-water, ages ago. 
“The Cyclolella bevolinensis (O. G. E.) which I have de¬ 
scribed looks very much like an Actinocyclus —in fact, is very 
closely allied to A. Rolf six (W. $.), and is figured by Van Heurck 
in his Synopsis (Blanche OXXIII, Eig. 6). In fact, it is 
probably nearly allied to that form which is so common along 
all coasts., and in the celebrated guano of Ichaboe, A pic a. It 
is also common, along with fresh-water forms, in the clay of 
Hatfield swamp, Few Jersey. This clay, by the way, is Upper 
Pliocene. 
“Epithemia musculus (E. T. X.l is present in small, or or¬ 
dinary-sized, frustules, and large and unusual-sized ones.” 
The Monterey earth to which reference is made was discov¬ 
ered by me in 1853 and is described in my Keport, 1 and in the 
Proceedings of the Academy of Sciences, Philadelphia. 2 It 
was partially examined by the late Professor J. W. Bailey. 
1 Geological Reconnaissance in California, 4to. 1855, and also in vol¬ 
ume V, Pacific R. R. Reports. 
2 Vol. vii, p. 328. 
