Geology of southwestern New York. — Harris. 169 
of 950 feet is somewhat arenaceous and micaceous, and contains 
fragments of coal as does the Portage in northern Chautauqua. 
(3). Below, the arenaceousness disappears ; and at a dfipth of 
1175 feet, a small Palceoneilo was found, which is certainly a 
Portage form. 
Assuming that the group in question begins at a depth of 950 
feet, it may be thus characterized : An argillaceous formation 
throughout ; generally steel gray in color, though interspersed 
above with occasional dark, thin, bituminous strata which become 
thicker towards the base of the group. In two instances, viz. , at 
depths of 1150 and 1725 feet, these dark shales assume a reddish 
or brownish hue, and represent, doubtless, similar conditions of 
deposition if not similar horizons to those termed " red rock " in 
the Fentonville well. 
A very perfect specimen of Cardiola retrostriata von Buch. 
(Glyptocardia sjieciosa Hall) was found at a depth of 2000 feet. 
At the base of the Portage group as represented in this section, 
there is a mass of slaty shale 100 feet thick. No representative 
of the Cashaqua shale seems here to exist, at least none such was 
recognized. 
GENESSEE SHALE. 
Gas was encountered at a depth of 2265 feet in far greater 
quantities than at any other place in the well. The shales at this 
point appear fissile, and give a brown streak as does the typical 
"Genessee slate." Below, however, they become slat}' and ap- 
pear like the black beds in the Portage above. 
HAMILTON GROUP. 
There is much doubt in the mind of the writer as to where the 
Genesee terminates and the Hamilton begins. As remarked 
above, the lower portion of the black shale deposit is b} r no means 
typical Genessee; neither can it be classified as Hamilton.* Beds 
of this group, however, do appear at a depth of 2330 feet, and 
continue with slight variations for ISO feet; they are gray, soft, 
and calcareous, and contain numerous fragments of shells. 
At a depth of 251(1 feet, a hard limestone makes its appear- 
ance ; black at first, but grayish below, and more or less cherty 
*It may lie. that there is here a partial transition from the New York 
system of classification to that of Ohio, wherein the black shales (2165 
ft.-2330 ft.) represent in part the Huron group of that state. 
