CAUDA-GALLI GRIT. 173 



a columnar structure ; for the strata arc iy>t vertically disposed, as we should infer from the 

 exhibition of the clifT itself: this is proved by the fact that fossils are found between layers 

 whose inclination departs only a few degrees from a horizontal position. The most ra- 

 tional conclusion which I have been aide to form of this instance of disturbance, is that 

 the strata have been simply crushed, so far at least as to obliterate the- planes of deposition ; 

 afterwards, the weathering of the cliff completes the change, and imparts to it. that peculiar 

 columnar appearance which I have attempted to delineate in the cut. 



This rock, though described under the name of grit, is quite an imperfect one : it is a 

 harsh shale, though massive as a whole ; and yet it is partially fissile, and splits into im- 

 perfect layers a quarter of an inch thick. No part of the rock is even-bedded, nor can be 

 split into handsome plates or layers, but it is always more or less lumpy and uneven. 



Thickness. This rock, in New- York, never exceeds sixty or seventy feet. It attains its 

 maximum thickness at New-Scotland, where it is well known in the bed of the creek at 

 Mr. Clark's, and where the layers for ten feet are impressed throughout with the flowing 

 appearance of a cock's tail. Below, in the road and at the base, the rock is bluish black, 

 and a few round or oval stems of vegetables often fall out of the mass, disconnected with 

 the principal part of the vegetable to which they belong. 



Extent or range of country over which the Cauda-galli grit prevails. 



1. Near Coeymans, Coxsackie, Catskill or Leeds, this rock appears in a southeastern outcrop in which 



it is represented only by its edge: at each of these places, it is broken and disturbed. 



2. The locality at New-Scotland has been referred to : it is the best place for an examination. At 



Schoharie, on both sides of Schoharie creek, it forms a terrace of a limited extent, with only a 

 slight dip to the southwest. 



3. At Cherryvalley, it is the surface rock near the great gorge one and a half miles northeast of the 



village : it is about fifteen feet thick, and crops out beneath the Onondaga limestone. It is also 

 exposed between Cherryvalley and Springfield, and on the road between Fort-Plain and Richford 

 springs, and in Warren and Herkimer counties. Farther west it is unknown, but the precise 

 point where it entirely thins out is not determined. 



For some general remarks on the fossil referred to, and for a more particular account of 

 localities, see Vanuxem's Report, pp. 129- 130. 



Agricultural characters. It forms a miserable soil, which only gives support to stunted 

 buckwheat : this at least is its character in Schoharie, where it forms a few limited terraces. 



Relations. Its position in the Helderberg range, at Schoharie and New-Scotland, has 

 been given. It stands in connection with the Oriskany sandstone below at Cherryvalley, 

 and with the Onondaga limestone above, while the rock reposing upon it at New-Scotland 

 is the Schoharie grit. For the disturbances which this rock has suffered, see Plate XX. 

 sections 5 and 6 ; and for its general relations, see PI. XX. section 1. 



