482 
GEOLOGY OF THE FOURTH DISTRICT. 
little south of the county line, a thick mass of concretionary sandstone, with regular strata of 
grey sandstone, is seen in the north bank of the Cowanisque creek. 
In order to give any definite information regarding the connection of these rocks with those 
of known character above, I have found it necessary to extend my examination as far as 
Tioga, Pa., seven or eight miles south of the State line. At this place the upper member of 
the Chemung group of New-York passes beneath the Old Red sandstone, dipping south at 
an angle of from 6° to 8°. The Old Red sandstone, a little south of this place, is about four 
hundred feet thick, of a brick red color, with beds of softer or shaly rock of the same color, 
containing fucoids and bones of fishes. The upper portion, containing the scales of Holopty- 
chus, often approaches in character to conglomerate. 
The Old Red sandstone approaches the south line of the county, towards its western limits ; 
and has been found forming a thin capping upon some of the higher hills in Troupsburgh. 
Here, as in other places on its northwestern margin, the rock consists of a thin layer of argil¬ 
laceous sandstone, highly ferruginous in character, and bearing a general resemblance to the 
iron ore of the Clinton group. Its decomposition stains the soil a bright red color, and, from 
these indications, it has been supposed that valuable beds of ore would be found. It is 
necessary to observe, however, that it is extremely doubtful whether this stratum will ever 
prove of any importance as an iron ore. In the southern part of the town of Greenwood, the 
soil is deeply stained from the destruction of this rock, but I have not found ihe same in place. 
In a section made from Dansville south, through the valley, to the Canisteo, and thence 
along Bennett’s and Troup’s creek to the south line of the State, nearly the same kind of 
rocks prevail as previously described, and in the same order of succession ; also in the valley 
from Patchin’s to Loon lake and Howard. 
The valley of Loon lake is the continuation of the Hemlock lake and Springwater valleys. 
In the neighborhood of the lake, large accumulations of drift rise in rounded hills fifty or 
sixty feet above the general level, and skirt the valley on either side; while beyond, the hills 
formed by the rocks rise to a much greater elevation. The commencement of the fossilife- 
rous strata of the Chemung group is at a little distance north of Loon lake. Few sections 
are exposed, and our observations are limited to the loose masses on the surface, and some 
shallow ravines where a few feet in thickness of rock are seen.* 
The country known as Howard Flats, is formed of drift hills and ridges but little elevated 
above the general level, being a high and not well defined valley, presenting outlets in various 
directions. I could not ascertain the depth of the drift, but the deepest wells do not reach its 
termination; and the absence of an impervious stratum in the gravel renders it often difficult 
to obtain water in sufficient quantities. 
* Loon lake is situated in a high valley; the hills on the east and west rise to a considerable height, but on the north and south 
there is almost a continuous level, forming an extensive swamp; the lake has no immediate outlet, but its waters supply Neil’s 
creek, which rises in the swamp, half a mile south. From the north end of the lake an artificial outlet supplies water for mills, 
and is continued as far as Patchin’s. 
