Diluvium. 



159 



Tom, I have shown that the difficulty of accounting for their situa- 

 tion, is not confined to the west part of the State. Another case still 

 more remarkable, exists on Mount Toby; although not embracing so 

 wide an extent of country. To the height of several hundred feet, 

 the eastern side of that mountain is very steep ; forming, indeed, in 

 some places, a mere precipice, very difficult to scale. A narrow val- 

 ley separates this side of the mountain from the extensive gneiss 

 range lying east, and rising gradually into mountain ranges, nearly 

 as high as Toby. Now on this steep eastern escarpment of Toby, 

 even to its summit, we find scattered bowlders of gneiss, of precisely 

 the characters of the gneiss in the north part of Leverett and in Mon- 

 tague. True, the gneiss range extends so far to the west in Monta- 

 gue, that a current of water from the north, or from a few degrees 

 east of north, would carry detritus towards the eastern slope of Toby. 

 But how is it possible that any aqueous agency could have driven it 

 up so steep a declivity? There are three remarks that may afford 

 the mind a little relief, perhaps, in this difficulty. One is, that on the 

 northeast side of Toby, are several ravines, running northeasterly, 

 with brooks at their bottom ; and these might have once presented 

 slopes less difficult of ascent, than at present. Another is, that the 

 conglomerate rock of Toby, may have been much worn away by 

 alluvial agents since the removal of these bowlders, and consequently 

 the eastern slope of the mountain may have been formerly much less 

 precipitous. Indeed, the great quantity of huge rocky masses that 

 lie along the base, renders such a supposition probable. Finally, 

 these bowlders may have been removed to their present situation ere 

 the valley on the east side of the mountain existed, and before the 

 elevation of the strata into their present situation. For I know of 

 no circumstances in the region, that are opposed to such a suppo- 

 sition. 



Mixed with the granite bowlders on the eastern slope of Hoosao 

 mountain, are masses of a peculiar kind of granite, distinguished by 

 its unusual tendency to disintegration. The parent rock, from which 

 it was derived, I have never yet discovered ; but predict that it will 

 be found along the western side of Hoosac mountain, in Clarksburg, 

 or farther north. 



The second argument that shows the direction of the last diluvial 

 current in Massachusetts to have been towards the south and south- 

 east, is based upon the existence of grooves, furrows, and scratches, 

 upon the surfaces of the rocks, that have never been moved from 



