150 Stria and Furrows of the Rocks of Western Neio York. 



Taconic mountains. No glacier alone could have removed them 

 to their present places, unless the Taconic range has since been 

 elevated, or the graywacke hills have been depressed ; and the 

 evidence of either supposition is not to be seen in the dislocated 



appearance of the strata. 



In Richmond, in Berkshire County, Dr. Reed has lately called 

 my attention to a long line of bowlders of serpentine, stretching 

 from the north part of Stockbridge across the valley of Rich- 

 mond, and up a ravine on the Taconic range, and over that range 

 into the valley beyond in the state of New York. Many of these 

 are large bowlders, from twenty to fifty feet long, and twelve to 

 twenty and forty feet wide, and eight to twelve feet thick. Of 

 course, these bowlders show little appearance of having been 

 rounded on their edges by attrition. Dr. Reed pointed me to 

 one bowlder, fifty feet by forty, and twelve feet thick in some 

 parts, and equivalent to forty feet square by ten feet deep, and 

 containing near one thousand three hundred tons of two thou- 

 sand pounds each. Several contain nearly one fourth as many 

 tons. These bowlders occupy a space of only a few rods in 

 width, while the graywacke bowlders are spread widely over the 

 valley. The large bowlder is on the west side of the road lead- 

 ing from the church northwards, and some more than half a mile 

 west of north from the church, on the eastern declivity of the 

 Taconic range. These bowlders would seem to require, from 

 their position and appearance, the combined machinery of large 

 bodies of ice and of a mighty flow of waters from the west of 

 north. It is only two or three miles north of the ravine just 

 mentioned, that Prof. Hitchcock pointed out the furrows worn in 

 the rocks by attrition and the mighty northern current, and at an 

 elevation as high as that of the ravine. 



Glaciers or icebergs and the strong current of waters, a union 

 of the two powerful causes, probably offers the least objection- 

 able solution of these wonderful changes, the polishing and fur- 

 rowing of the rocks, and the transportation of bowlders. In- 

 deed, the polishing might be done by great masses of floating ice 

 in their mighty pressure upon the earth and gravel and stones 

 upon the surface. If the motion of the glacier now polishes the 

 rocks beneath, or even only smooths them, the motion of massive 



ice would effect the same, and also cut the striae and grooves and 

 furrows. 



Rochester, N. Y., Sept. 17, 1842. 



