STOCKBRIDGE LIMESTONE. 157 



these two beds of limestone (the one filHng the central part of the Hoosic valley, and the lateral 

 or western one) really commingle at the southern extremity of Stone liill. 



Some of the difficulties relating to the continnily and identity of the several belts of lime- 

 stone arise probably from the uplifts which form the short spurs of mountains, which, rising 

 up in rather interrupted lines, create confusion by crowding the beds of limestone, or other 

 masses, out of the true line of their strike. By admitting this westerly mass of limestone, 

 or that on the eastern base of the Taconic range, as one distinct from the Adams range and 

 that of the Hoosic valley, we shall have tliree parallel beds of the Stockbridge limestone. By 

 reference to section 46, it will be observed that I have represented a bed or mass of limestone 

 at tlie west base of Saddle mountain, marked 2, or Second bed of limestone. This is full 

 five hundred feet thick, lies in the magnesian slate, and does not rest upon it, or rather against 

 it, as has been supposed by some geologists. I suppose this rock to form the gi'eat repository 

 of die Ashford, Lanesborough and Stockbridge marble. It appears on the south slope of this 

 mountain ; or that slope which forms the north side of what is called the Hopper, immediately 

 beneath Graylock. It strikes across the deep ravine which runs up to the Hopper, and 

 appears forming a part of the next mountain south, which is a west spur from Graylock ; 

 and in the same direction or strike, we find the New-Ashford quarries of marble. In the 

 section just referred to, I have represented upon the right of the fracture, at figure 2, curved 

 strata. These curved strata form, I suppose, the valley of the Hoosic, or mainly that part 

 of it on which the pleasant village of Williamstown, with its College edifices, is situated. It 

 will be observed by the most careless that the strata of limestone are remarkably bent and 

 contorted, forming in many instances double curves. 



In relation to the two masses, one forming the valley of the Hoosic, and contorted in this 

 remarkable manner, and the mass represented as the second bed of limestone, and plunging 

 into Saddle mountain, I now consider them as the same, the latter having been broken from 

 the former by an uplift. We have, however, to go so much by conjecture in these questions, 

 that it is rare that we can enjoy the satisfaction of being certain we have the truth. 



Again, referring once more to the contorted limestone, I am often disposed to attribute 

 these flexures to other causes than lateral pressure. They appear often too much bent and 

 folded upon each other, so as to look like concretionary masses ; and in some cases, these 

 irregularities might be produced in the same manner as the contorted layers in clay beds ; by 

 deposition upon irregular surfaces, washing out the lower layers, by which those above are 

 left unsupported ; or by irregularities in currents, etc., by which unequal and irregular depo- 

 sits take place. 



I will now leave this subject, perhaps without having thrown much light upon it ; in hopes, 

 however, that it may yet be elucidated by abkr minds. 



