480 
GEOLOGY OF THE FOURTH DISTRICT. 
STEUBEN COUNTY. 
The general character of the surface of this county is similar to all those of the southern 
range. A series of broad irregular hills with low valleys occupy the greater part of the county. 
It is also marked by several deep valleys, which present broad alluvial bottoms. The valley 
extending south from Crooked lake, the Conhocton, the Canisteo and Tioga, are the principal; 
these all unite in one, below Painted-Post, communicating with the Susquehannah. 
The rocks of this county are of the Portage and Chemung groups, the line of demarcation 
between the two being much better defined than farther east. The lower group appears in all 
the deep ravines and along the water courses in the northern part of the county, while the 
high grounds are occupied with those of the next group. After leaving the head of Crooked 
lake, the rocks of the Portage group are not again seen in the county going southward, although 
upon the shore of Seneca lake they extend still farther south, from the greater depth of that 
valley. 
Along the western shore of Crooked lake, the rocks consist chiefly of sandy and slaty or 
argillaceous shale, the former rippled or undulated, showing that each thin layer of the shale 
was subjected to the action producing the rippled surfaces, and this action continued uniform 
throughout the whole deposit. Alternating with the greenish shale just noticed, is a darker 
slaty shale containing fossils. At some localities occur a few thin layers of sandstone, but 
these are not abundant until we approach the head of the lake. 
Four miles below Hammondsport, in a ravine on the bank of the lake, can be seen a con¬ 
cretionary stratum of impure limestone, composed of roundish or irregular masses cemented 
together by an argillo-calcareous cement. In other localities, the concretionary forms are not 
so distinct; and the whole bears the character of an irregular mass, separated in various 
directions by thin seams of slialy matter. So far as examined, this stratum bears a very uni¬ 
form character; it disappears beneath the lake on the east side, one mile below Hammonds¬ 
port. This limestone has been burned, but found loo impure for quick lime, though it pos¬ 
sesses some of the characters of hydraulic cement. 
At Hammondsport, in the ravine above Mallory’s mill, we find about three hundred feet of 
rocks exposed, belonging to the Portage group; they are well characterized by the Fucoides 
graphica. Few fossils other than fucoids appear through this thickness, though higher in the 
ravine are some fossils peculiar to the next grpup. The mass exposed consists, in the lower 
part, principally of shale and thin layers of sandstone, and at a higher point numerous layers 
of sandstone from four to ten inches thick. The edges of all the layers exposed, are covered 
with crystals of selenite, or crystallized gypsum. About one mile from the mouth of this 
ravine, an excavation for coal has been made in the black shale, which alternates with the 
sandstone and olive shale. The indications of coal at this point were a few fragments of 
vegetables, iron pyrites, and the odor of bitumen arising from the shale; all these were sup- 
