Geology. 129 
uscide, of whic mmon house fly is an example; it may 
probably" be referred 6 a ean in which they are nearly or Bre 
wanting, and where the larve ordinarily feed upon dea imal 
matter or upon cad led, plants. Belonging to the same aitap 
and sgn. <hahoa soe # or 
in sal t 
eee podiianay: they at rat discovered in the saline waters 
e Nevadan ‘takes, po Professor Denton states that dipterous 
laren erabanly of a similar kind, are found in great numbers in 
lakes impregnated with acam nad Pree is probable that the shales, 
in which these remains occur, were deposited in such a lake.’ 
About a mile west of the “ Petrified Fish Bed,” is a cut along 
the railroad which passes through a moderate thickness of buff, 
These rocks hold a position about one hundred feet above the petro- 
leum shales which contain the fish remains, and therefore the date : 
their existence may be regarded as somewhat — eet ate thoug 
belonging to the same basin. Prof. J.S. New iven these 
plants a partial examination, and communicated De a eae 
teresting notes in the form of a let 
ocks enc’ all’s mine are 
more significant, as fre i include a Platanus pthentiei which 
is certainly differe: video), ¢ 
you at Carbon Station, me at he Seceich of the Yellow Stone. 
Every collection of fossil — received from the — of the 
west brings to light many new species, and the great versity 
which they exhibit proves yolk a number of plant-bearing hori- 
zons, OF pet arora ti of the + sigh in the one's flora. 
Amon ng your Green River plants, are only some half dozen 
species, So well preserv iad as to be capable of romp oer: identifi- 
Am, Jour. Sc1.—SEconp Serizs, Vou. L, No. 148.—Juty, 18 
9 
