acknowledged Devonian fauna, and holds a silat beneath fifteen — 
dred to two thousand feet of other Devonian strata, we find ay as we go 
westward from New York, assuming a more and iferous 
character, so that in northwestern Ohio, its fossils become as is decidedly 
Carboniferous as those of the Burlington limestone; and that again in 
sate beds above, that no very sharp line of separation can be 
n betwee wana we ma y reasonabl infer that if the same 
| were exposed midway between the Mississippi and the Mountains 
. in ‘hi, are mim synchronous with emung of eastern New York. 
we may cast Paleontology i the winds, so far as the identifi- 
cation of strata is concerned. 
» But it is asserted with much confidence, that such are the facts, at lelie 
in tracing the Chemung westward from eastern New York to Iowa. It 
e 
"OQ. 
i= 
a. 
‘o 
i=} 
& 
a 
i] 
4. 
°y¥ 
=} 
“= 
se 
° 
Q. 
° 
i=} 
ima 
or 
& 
au 
es 
= 
S. 
9° 
—— 
g 5 
age: 
Loolad 
i 
a 
= 
oO 
a 
ot 
aaa 
=] 
ba 
ae and that too, as was supposed, upon palzo ntological grounds, 
that the Rockford Goniatite bed and the Black Slate of the west, belong 
to the horizon of the Marcellus Shale; and yet it is now admitted that 
| the first must be carried up at least as high as the Chemung, and that 
the latter may represent the Genesee Slate instead of the Marcellus 
Shale. Again it is not very long since it was maintained with quite as 
much confidence that certain pert in Se pe oe me aries: 
types of Trilobites, belonged to the orizon ; 
yet, thanks to the rostohed paleontological skill of Mr. Billings, of Can- 
ada, and : Barrande, of re it is ose known that they really 
belon at the base of the Silurian Series. ; 
5. g far down as, oder die Zechstein-Formation und das Rothliegende, 
von Dr. Hanns Broxo-Gursi7, Leipzig, 1861—4°, nb 130, 23 aoe 
—This aaitinash memoir on the group of rocks called Permian Per heer 
chison, has reached us from the author. WwW 
number to notice some of the conclusions, and esally to sauea a 
and American fossils. 
It was first proposed in 1859 by M r 
(Magnesian 
tion consists of two parts,—the m ; ste agn 
Bimestone oa the wipae anton wie the Roth-liegende Looe _ Gres 
forma 
oot will “ipa that in 1859 Sir R. I. Murchison published i in 
Axe. Jour. Scr.—Szcoxp SERtEs, Vou. XXXIII, No. 99.—Mar, 1863. 
54 
