Geology, Sz-c. of the Connecticut. 15 



will probably visit. I refer to the main body of that enor- 

 mous vein containing the green tourmalin, rubelite, &c. 

 in Chesterfield. We think it might even admit of a ques- 

 tion whether this be a bed or a vein. 



The veins of which we are now speaking are doubtless 

 contemporaneous ones — that is, such as were consolidated 

 at the same time with the rocks they traverse; There is no 

 seam or layer of another rock at their sides, but they are 

 usually so firmly united to the rock which contains them, 

 that they are separated from these with as much difficulty 

 as they are broken in any other direction. I have, how- 

 ever, frequently noticed a seam traversing the middle of the 

 vein — so that if the rock they traverse be broken up, one 

 half will cleave to one side and one half to the other. 



A real lusus naturae exhibiting the fine cohesion of these 

 veins to the rocks they traverse, now lies before me. A slab 

 of granite being a vein 2^ inches thick, 10 inches broad, and 

 20 inches long, curved a little upwards at one end, forms 

 the base of the specimen. From the centre of this, rises 

 perpendicularly a bladed, taper-pointed column of a pecu- 

 liar limestone, only 2 inches thick, 10 inches broad at the 

 base, and 26 inches high, appearing as if mortised into the 

 granite. The contrast between the light coloured granite 

 and the dark gray limestone, is very striking. The secret 

 of its having been brought inio this singular form appears 

 to be this. It was found in a mountain torrent in Conway, 

 and the granite doubtless once formed a vein in the lime- 

 stone. On one side the limestone has been entirely worn 

 away by the water — and on the other side, it is worn so as 

 to leave only the bladed column above described, which 

 still adheres firmly to the granite. 



I have said that these granitic veins are contemporane- 

 ous ones : And it would seem that the judgment of no man 

 could be so warped by theory, as to believe, after examin- 

 ing them, that they wei'e once fissures made in the rocks 

 they traverse, after these vjere consolidated, and that these 

 fissures were filled by a solution of water above, or by a 

 fiery furnace beneath. There is just as much reason for 

 believing that one of the constituents of granite, quartz for 

 instance, was introduced into the rock in this manner after 

 the other constituents were consolidated; or that the imbed- 



