13(5 CHAMPLAIN DIVISION. 



Another great line of fault exists upon the eastern suit- of the Hudson and Champlain 

 rallies : it in fan has elevated the country in such a manner thai the line of fracture 

 bounds the valley. The mosl conspicuous eminences are near this line, and the rocks are 

 the dates of the Taconic system, surmounted bj one <>r more varieties <>f the Calciferorrs 

 sandstone. Qreenbush, Baldmonntain, Granville, Whitehall, Addison, Burlington, Mil- 

 ton, are upon this line of fracture, audi might mention many other intermediate points 

 where all the phenomena I have stated may lie witnessed. 



The agent which determined the existence and direction of this great longitudinal dis- 

 placement of the strata, gave Origin also to the valliesof the Hudson river and Lake 

 Champlain ; or, it may he more properly said, that the boundaries were first determined by 

 it, and that then the rallies themselves were formed by denudation. The entire series of 

 sedimentary rocks, which have been elevated and thrown into an inclined position, lie 

 between tin- base of the Helderberg and the Hoosic mountains. But in taking so wide 

 an area as this, we undoubtedly embrace fractures more ancient than the one which forms 

 the valley of the Hudson. This, though it disturbs the Hudson-river rocks mostly, yet in 

 one section of country it passes through a prolongation of the Helderberg division ; showing, 

 in this fact, that it was really of a date as late as the Onondaga limestone. But the Taconic 

 rocks were elevated, and made to assume an inclined position, before the deposition of the 

 oldest member of the New-York system : this follows from the unconformahility of the 

 two s\ stems ; but it is impossible to fix upon the era. The Taconic rocks rarely occur su- 

 perimposed upon one another, as we see in the arrangement of the Helderberg division, 

 and in the slates and shales above; and hence, it is, that though they may have been 

 fractured many times between the deposition of the granular quartz and the taconic slate, 

 still the relative position of the masses is such that no rational conclusions can be formed 

 in regard to the era in which they took place, whether in the earliest or latest period of 

 the system. 



Another limited fracture appears on the southeastern side of Becraft's mountain, about 

 three miles southeast of Hudson. On one side the Taconic slate appears supporting a 

 fragmentary mass of the Calciferous sandstone ; on the other, the inferior members of the 

 Helderberg division, the thin-bedded waterlimes and pentamerus, beneath which are the 

 gray sandstones of the Hudson river. The relation of the latter mass is illustrated in 

 fig. 20. 



i .. 20. 



a. Pentamerus limestone. e. Talus. b. Thin-bedded wateilimes. c, e. Hudson-river scries. 



