IOWA ACADEMY OP SCIENCES. 
53 
Eunotia diodon (Elir.). Rivers, springs, rapids, on wet rocks 
and fossil. 
Eunotia gracilis (Ehr.) Raheuli. In boggy, swampy places. 
Eunotia major (Wm. Sm.) Rabeuli. In fresh water every- 
where. 
Stauroners phoenecemteron ( Nitz. ) Ehr. Cosmopolitan. 
Oystopleura gibba (Ehr.) Kunze. Common in fresh water; also 
fossil and marine. 
Cymhella oyinbiformis (Kiietz.) Breb., var. parva (Wm. Sm.) V. 
H. Common everywhere in fresh water. 
Hantzschia amphyoxis ( Ehr. ) Grun. Common everywhere in 
fresh water. 
Judging from the above and from evidence which does not 
appear here, i. e., the comparative number of individuals in 
each species, the condition was probably that of a shallow 
bog, subject to gentle overflows from some creek or river. 
DIATOMACEOUS EARTH IN MUSCATINE COUNTY. 
BY J. A. UDDEN. 
While at work on the geology of Muscatine county last sum- 
mer, the writer found some diatomaceous earth in tbe south 
bank of the creek which runs west near the south line of sec- 
tion fourteen, in Cedar township. It is associated with a peaty 
layer, which overlies it, and which appears somewhat dis- 
turbed. This peat is overlain by fine laminated sand and silt, 
which here forms the base of the loess. Below the peat bed 
and the diatomaceous layer there is a white sand without a 
trace of ferruginous stains. Boggy conditions are indicated, 
or perhaps the conditions of a lake or pond. The diatomace- 
ous earth itself does not lie in a continuous layer, but in a 
broken layer, or in small pockets, which are scattered. It has 
a peculiar dull, pink color, and this has lately enabled the writer 
to find small lumps of it in the peaty soil under the loess in Scott 
county, near Davenport. It was from this loess that the 
remains of a mastodon have been reported by Mr. Pratt. 
