i:t8 



CHAMPLAIN DIVISION. 



only broken at quite regular intervals, but have been made to assume an inclined position. 

 They only require to be uplifted a little more, in order to resemble (he strata upon the 

 eastern side of the Hudson river. 



Fig. 22. 



1, is the Calciferous group. 2, consists of the Birdseye limestone. 3 & <1, Trenton limestone. The dip is 10° south. 



Many other instances might be given, illustrating and supporting the same views, both 

 in the Champlain and Mohawk valleys ; and it is perhaps proper to remark, that it is 

 principally in these valleys, and other parts of the State adjacent to the Primary system, 

 that the changes of the kind I am describing are found : they are scarcely, if at all, to be 

 found at only a short remove from these ancient rocks. 



* 



Fig. 33. 



The falls of Montmorenci exhibit an interesting- view of the rocks, resembling the frac- 

 ture which has been already described. It is upon the western limit of this line of fracture. 

 a, b, c, d, TJtica slate, Trenton limestone, Calciferous and Potsdam sandstone, in a hori- 

 zontal position. /. Utica slate thrown down so as to dip at an angle of 60 or 70°, and 

 leaning against the gneiss that forms the precipice over which the water is precipitated. 



§ 15. Thickness of the rocks of the champlain division. 



The following is the best estimate of the thickness of the individual members of this 



division, that I have been able to make : it of course applies only to these rocks as they 

 exist in the State of New-York. ', r- r 



1. Potsdam sandstone 300 feet. 



,, , 2. Calciferous sandstone 400 



3. Chazy limestone 150 



. , ^ 4. Birdseye limestone 50 '' ' ' ' "' 



5. Isle-Lamotte marbfe 25 ''' '■■■"! /''.•.• i. id,-,; 



• 6, Trenton limestone 400 



7. Utica slate 100 



I ' ^ ' , 1 . 8. Shales and gray sandstone. . 700 ; 



9. Oneida conglomerate 400 • ' 



Total thickness 2525 feet. 



