Claypole.] 234 [Sept. 21, 
The following extract from the Geology of the Fourth District of New 
York will show the close resemblance between the rocks at the two places: 
““The thick-bedded sandstones at Portage form the terminal rocks of the 
group.’’ ‘The upper part consists of thick-bedded sandstone.”’ ‘‘ The 
arenaceous strata of the Portage group are always more argillaceous than 
those of the Chemung group.”’ 
It appears from Prof, Hall’s description of the group that it begins with 
beds very free from sand—the Cashaqua shale—and ends with a heavy 
thick-bedded sandstone. At least this is its character at its eastward ex- 
posures on the Genesee river. Farther west the sand, as usual, disappears 
and the group contains little except shale. 
The Portage group in Perry county comes, therefore, as near to the typical 
Portage group in New York, as can be expected—near enough in strati- 
graphical and paleontological characters to give full confidence in their 
identification. 
I may add, in conclusion, that some of the shale beds near the Portage- 
Chemung sandstone are much valued locally as whetstones. These ap- 
parently occur both above and below the sandstone. 
In one place also, a bed of light-colored brown hematite has been exposed 
lying on the top of the sandstone and about eighteen inches thick. This 
is the only case of the occurrence of a bed of iron ore of any appreciable 
thickness in the Chemung of Perry county. No trial has yet been made 
of it, but judging from appearance it would not be of high grade. 
The facts given above are useful in that they enable us to separate 400 
feet from the great mass of olive shale in Perry county. The separation of 
200 feet, as the Hamilton Upper shale, was mentioned in the beginning 
of this article. The total thickness of the olive shales of VIIT has been 
given in the neighborhood of Newport, at about 5500 feet, thus divided : 
ONC heath ag MMR eR rae oni io ta Weer ons Orc nnniun, uae panenegeye th, 10,0] 
POPC siisvie cu UN ale ele alintile nhs cavities Va Wee sles divenie nt COU A DOUb: 
PEAR Es hie vc \iels Hal Wisin 04 Hea telvlnun ni eip Welvlelsd Mass tinis ian LAND) 
5520 
3ut these measurements are much exaggerated, They have apparently 
been made along the Juniata, without noticing a fold which occurs at 
Inoculate run, and the effect of which extends beyond the river. The 
ground is very difficult, but the following figures, which I have ob- 
tained with considerable trouble and checked as carefully as was possible 
with the limited time at my command, are certainly nearer the truth for 
the neighborhood of Newport : 
CGI T Soo: oho, dial Hivinsy Ninh, pans eine ev ia ek RENE TO Wie Hsiao vue 4 8000 
Portage. we H Pele Nie OAihid alwveluni aiden he Vateee OUD 
GONCSEC so. 0.6 vies Meee blo Hy WE debs Hole MV Wellpee Sr Rime rere: ie OU 
8400 
It thus appears that after the sepa ration of the 600 feet above mentioned, 
