ae 
On the Triassic Rocks of Kansas and Nebraska. 31 
dication, according to the crystallogenic views which are rapidly 
eing generally adopted at the present day, of the agency of 
water, at or near the ordinary temperature, in its formation. 
se har for the sake of simplicity, as Breithaupt, von Ko- 
bell, Frankenheim and Rammelsberg have done,* that pyrrho- 
tine is priteeubphed of iron, the action of oxygeniferous hese 
upon it in the formation of pyrites and limonite, may be re 
sented by the rather simple equation 
8FeS+24HO+20=FeS? +Fe?0*, 1$HO+HS, 
the sulphohydric acid formed entering into solution in the water, 
and subsequently either undergoing oxydation in its turn, or 
issuing in sulphur springs.t 
Art. VI.—On the so-called Triassic Rocks of Ki oe and Nebraska ; 
by F. B. Mex and F. V. Hay 
In several of our Ale cae on the geology of Nebraska, 
we have mentioned a formation (No. 1 of the Nebraska Section 
consisting of reddish and yellow akon and various colore 
clays, with seams and beds of impure lignite, holding a position 
at the base of the Cretaceous series 0 though 
entertaining some doubts respecting the exact age of this forma- 
tion, we have always pl it provisionally in the Cretaceous 
system, in our eal sections 
ving | rough Mr. lived that a aaaagh similar 
Hex of strata, nolding apparently the same position, occurs in 
northeastern Kansas, we placed these latter beds on a parallel 
with No. 1 of the ebsisks section, in a paper read before the 
Phila. Acad. Nat. Sci., May, 1857. Soon after the publication 
of this paper, however, a few fossils Mr. Hawn had shipped to 
‘us some time before, fro rom a bed near the base of a section of the 
mani “Mint in drawing a parallel between the Kansas and 
Nebraska formations, we » had carried No. 1 too low in Kansas, 
by bringing it down so as to include the bed from which these 
had een obtained. 
* Handwérterbuch der Chem. Lieb. Pogg. and Woehler, v, 62. 
+ These views in a future communication, to be othe mi 
whenever I shall have been able to complete my chemical meg pe of the min- 
erals collected in this egy and in which I propose to bring forward mah | 
ions regarding the gee pee of the crystalline army of the 
the included metalliferous ve. 
_ States, and the nature and origin of 
