194 THr, PilENOMENA OF DRIFT, OR 



Stranding of these along the low region of Cape Cod, as upon 

 our mountains. 



1 think, however, it is generally true, that these moraines are 

 most common in mountainous districts; or rather, about midway 

 between the highest and lowest levels. The valleys of existing 

 rivers and tlic vicinity of gorges in mountains, most abound with 

 the detritus under consideration. The moraines more usually 

 preserve then- original form near gorges no longer occupied by 

 currents : as our rivers have genei-ally modified their form, in a 

 mode to be hereafter described. And 1 doubt not, that as the 

 waters retired, either by subsidence, or the rise of the land, large 

 quantities of ice would be urged by the rivers along their chan- 

 nels, acting somewhat in the manner of descending glaciers ; that 

 is, forming lateral moraines, and terminal too, where the hills 

 closed in upon the river so as to stop ihe ice. 



It may be suggested that all our moraines were produced in 

 the manner just pointed out; and had no connection with that 

 southeasterly impulse, which scattered the bowlders. But this 

 idea is opposed by several facts. And first, the smaller detritus 

 of moraines, so far as I have observed, had the same northern 

 origin as the bowlders ; although the moraines are rarely carried 

 as far as many of the blocks. Secondly, the western slopes of 

 mountains, running nearly north and south, abound far more with 

 these moraines than the eastern slope ; as if all the detritus accu- 

 mulated on the eastern slope, were driven southeasterly across 

 the valley, until obstructed by its eastern side. Thus, in the 

 valley of the Connecticut, we find very few striking examples of 

 these moraines along its west side, or in the valleys of the rivers 

 that descend the eastern slope of Hoosac mountain into that 

 valley. But along its eastern side, and for a considerable distance 

 up the primary hills that form its eastern boundary, they abound 

 every where, and are often most striking. So along the eastern 

 side of the Taconic ridge of mountains, we see but little drift. 

 Yet along the base, and extending up the valleys for some dis- 

 tance on the western side of the Hoosac range, that runs parallel 

 to the Taconic, and bounds the valleys of Berkshire on the east, 

 moraines are very abundant. So that while we find evidence 



