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[Assembly 
rocks and fossils, succeeding the limestone which follows. The Caly- 
mene biifo, and Cryphseus calliteles are characteristic fossils of this shale 
" The Tally limestone''^ succeeds the shales just described: the great- 
est thickness of this mass of limestone, in Seneca county, does not ex- 
ceed sixteen feet- but it extends over a great area, maintaining a very 
uniform character. It is of a light bluish gray colour^ in some locali- 
ties blue, fine grained and very compact; it contains few fossils, and 
those of the same species as in the shales below. This rock presents 
many of the characters of the Seneca and other lower limestones; and 
in hand specimens does not appear to differ from these, but is readily 
distinguished by its associations from any of them. The mass consists 
of three or four layers, for the most part of uniform thickness. It is not 
generally fit for building stone, being traversed by seams in all direc- 
tions, and breaking into irregular masses. In some localities the whole 
mass crumbles, on exposure, into small fragments, from half an inch to 
three inches in length and breadth, but presenting no further tendency 
to decomposition. The fragments are all clay coloured on the exposed 
surfaces, resembling in this respect some of the harder gypseous marls. 
There are a few localities where this rock is very compact; the lay- 
ers are from one to two feet thick, and it can be quarried of any re- 
quired dimensions. Its northern edge extends in a curve entirely across 
the county. From where it is first seen it may be followed in a north- 
easterly direction to a point two miles north of Ovid village, where 
it is quarried for burning into lime, and for various other purposes, on 
the land of Mr. Thompson Johnson. This point is the greatest north- 
ern extension of the curve. From here it gradually bends to the south- 
east, and appears on the Cayuga lake shore, in a line nearly east from 
its point of appearance on the Seneca lake shore. This curved out- 
cropping of the mass is merely the eflfect of erosion; the greatest force 
of the northern current being in the channels of the two lakes, its force 
was diminished towards the centre of the county, which consequently 
left the limestone extending farther north at this point. 
This mass being so distinct in appearance from the shales above and 
below, manifests, very clearly, the beautiful undulations produced by 
subterranean action upon the contiguous rocks. At the point where the 
limestone first appears, in a ravine near the lake shore, it is sixty feet 
above the level of the water; half a mile south of this, it comes to that 
level, and after disappearing beneath the water for a short distance ri- 
ses again toward the south and soon disappears from the lake shore. 
