CHAMPLAIN DIVISION. 127 



berg appear, occupying a position immediately upon the thick-bedded sandstone of the 

 Hudson-river group. o 



If a tangent line, then, be drawn in the direction of Utica, so as to touch the Helderberg 

 spurs as they come up from the south, this tangent line will form a very correct line of the 

 boundary of this division. It may be carried on in the direction of Rome, and terminated 

 upon Lake Ontario. South of this line there are no rocks belonging to the lowest division, 

 except at the opening of the north and south vallies with the Mohawk. Thus, at Scho- 

 harie court-house, the Hudson-river rocks really underlie the clays and alluvions as high 

 up as the bridge southwest of the village. So they may probably be traced a short distance 

 up some other minor vallies lying parallel with this. They are all vallies of erosion, and 

 the superior rocks have been removed, and hence the exposure of the lower ones in the 

 bottom of these excavations. 



We have, then, nothing more to do with the Champlain division in the whole of New- 

 York south of this imaginary line : neither are the rocks superior to those upon the north 

 side of it ; not a fragment in place, or even a boulder. 



But here it is necessary to state, that on another route, we find the Champlain division 

 largely developed. Departing from the eastern slope of the Helderberg range, and avoid- 

 ing the higher spurs, w T e shall find the lower division continuing in the direction of 

 Coeymans, Catskill, and onwards to Kingston, and thence to the High falls of the Ron- 

 dout. The eastern side of this route is mostly the lower division. The only exception is 

 at Becraft's mountain, near the city of Hudson, where the Helderberg rocks form an in- 

 considerable area : it is the only place where they appear east of the Hudson river. 



The Hudson-river group stretches from the northern base of the Helderberg range, 

 passing through Schenectady and onwards north of Ballston, and thence northeast towards 

 Sandyhill. On the route of the canal from Schenectady to Albany, and at about four miles 

 east of the former place, we meet the disturbed belt, where the shales and slates are curved, 

 arched and broken, or form undulating planes for a great distance. These disturbances 

 are well exposed along the route of the canal. Near the Cohoes, they may be examined ; 

 and even here, although badly broken up, a faithful observer will find the fossiliferous 

 bands. So a few miles west of Milton, opposite Poughkeepsie, the disturbed masses of 

 the Hudson-river group disclose the fossiliferous beds. But in the slates of the Taconic 

 system, though less broken and disturbed, we find no bands charged with mollusca. Those, 

 therefore, who deny the existence of the Taconic system, should be able to account for and 

 explain this fact ; and should this fact be sustained by continued observation, it is itself 

 of sufficient importance to establish the position we have taken in regard to a system of 

 rocks beneath and older than the Silurian or New T -York system : it would mark clearly and 

 ineffaceably a line of demarkation between the two systems we contend for. And should 

 mollusca in the taconic rocks be discovered hereafter, it would not affect our position, 

 unless indeed they were identical with those of some part of the superior system ; and 

 even then how are we to explain the fact of superposition 1 Now, the rocks below the 



