484 
GEOLOGY OF THE FOURTH DISTRICT. 
On the land of Mr. Davis, at Lagrange, a salt spring rises in the green shale ; the water 
is turbid, and emits bubbles of carburetted hydrogen gas. Several years since, salt was made 
at this place, and previously by the Indians. There are, however, no inducements for dig¬ 
ging; for, so far as we know, no salt springs of importance are found in this rock, and it is 
probably only such a one as might occur in any marine formation. 
There are numerous beds of lake marl and tufa in this county, some of which are im¬ 
portant as furnishing lime. Two miles northeast of Arkport, there is a bed of this kind which 
furnishes a considerable quantity of lime. There is another similar one south of the village, 
from which lime was formerly burned. In the town of Troupsburgh there is a bed of this 
marl, but it has not yet attracted notice. There is an extensive deposit on the Canesaraga 
south of Dansville, from which lime is burned. The summit level between this creek and 
the Canisteo presents an extensive muck swamp, and some beds of marl, but their extent 
has not been ascertained. 
ALLEGANY COUNTY. 
The general elevation of this county is higher than Steuben and Chemung, while the rocks 
are the same ; a difference produced both by a greater thickness of the mass, and a dip to the 
east or southeast. 
The northern part of the county is occupied by the Portage rocks; the lower portion of 
these rocks, however, is rarely visible, except in deep ravines or water courses. The upper 
part of this group forms the cascades and deep escarpments along the line of their northern 
outcrop, in many places extending beyond the limits of the county into Livingston and Gene¬ 
see. At the falls on the Canaseraga, in the town of Burns, the Portage rocks are much ex¬ 
posed ; but it is at Portage, as has been before described, that they are fully developed, and 
may be seen in perpendicular cliffs from two hundred to three hundred and fifty feet high. 
The same rocks are traced along the Genesee valley for several miles, when they are suc¬ 
ceeded by the olive shaly sandstone and black micaceous shale, which occupy a part of the 
towns of Eagle, Pike, Centreville, Burns and Portage. The thin layers of sandstone inter- 
stratified with the black shale, and also those usually succeeding it, are quarried on the Wis- 
coy, a mile west of Pike centre, near Pike hollow, and at many other places along the out¬ 
crop and in the ravines and valley sides. 
The upper part of the Portage group consists of a mass of slightly argillaceous sandstone, 
compact and fine-grained, from one hundred and fifty to two hundred feet thick, in some 
