408 [Assembly 
succeeding the red sandstone on the Tioga. Should these facts be es- 
tabhshed, it will prove the thin red rock to be the continuation or 
equivalent of that great mass of the old red sandstone. 
In examinations further south, I have not been able to discover the 
red sandstone, neither along the Allegany and its tributaries, and I 
am informed by Mr. Horsford that he saw nothing of it in his journey 
down that river as far as Warren, Pa. which brings us to the northern 
limits of the coal. 
From the fact that this red sandstone does not appear to have been 
recognized as a thick mass east of the Tioga, it affords us some valuable 
facts regarding the manner of deposition in many of our rock masses, 
being in deep basins of greater or less extent, some rising rapidly from 
the centre, and causing the abrupt thinning out of the deposits ; others, 
from their more gentle ascent, admitting the gradual thinning of the 
strata, and their continuance over a greater area. The condition of 
the ancient surface, together with the different sources of materials de- 
posited, have caused many difficulties in identifying strata at distant 
points. The latter is a subject of great interest ; for we can readily 
perceive that a mass of lime or sand-rock, although now spread over a 
great extent, must have had an origin elsewhere than at the point where 
we may chance to examine it ; and we reasonably infer that the thicker 
portions of the mass are nearer the source of the material, from whence 
it flowed over the bottom of the ancient ocean in the state of soft mud, 
its direction being determined by a current, or otherwise, until it thin- 
ned out at a distance from its origin, in proportion to the quantity of ma- 
terial supplied. 
Whenever it happened that sand and mud, or clay in a state of ex- 
treme comminution, were furnished from the same source, the sand 
would be first deposited, and the clay last ; while particles of carbonate 
of lime might be intermediate. In the strata of western New- York, 
materials of the same nature appear to have come from different direc- 
tions ; thus we find the Lockport limestone thinning out in its eastern 
extension, and again the Tully limestone thickest at the east and grow- 
ing thin towards the west. 
The source of sand appears to have been at the east ; for all the strata 
of the upper rocks grow more sandy in that direction, and more argil- 
laceous in going west : either clay was furnished from the west, or 
