16S THE PHENOMENA OF DRIFT, OU 



this continont. But it may be stated in general, that the predom- 

 inant direction of om- mountain ridges and the correspondent 

 valleys, is either norlh-north east and south-south west, or nearly 

 north and south. The former course embraces the Apalachian 

 mountains, extending nearly parallel to the coast through most of 

 tiie middle and southern States, and embracing also the principal 

 ranges of New England, especially the White Mountains. The 

 north and south ridges embrace the Green and Hoosac Mountain 

 chain, and several minor ridges in New England. Now it is 

 obvious, that since the force which transported our bowlders took 

 a southeast direction in general, it must have earned them ob- 

 liquely across most of our mountain ridges. And this is one of 

 the most striking facts in the phenomena of diift in this country. 

 For I think I have probable evidence that they were can-ied over 

 our highest mountains; and when one stands upon a precipitous 

 ridge, three thousand, or four thousand, or even five thousand feet 

 high, and sees in the bowlders around him, and in the fuiTows 

 on the rocks beneath his feet, evidence that this denuding and 

 transporting force has been exerted even at that height, and con- 

 sequently has swept over all the lower yet lofty ridges that fill his 

 circle of vision, he cannot but feel that the agency, whatever it 

 was, has been wide-spread and gigantic. 



The facts which have been stated respecting the dispersion of 

 bowlders from the parent rock, appear to me inexplicable without 

 calling in the joint agency of ice and water. Nor does it appear 

 suflicient to suppose that the water simply lifted up and bore 

 away masses of ice loaded with fragments of rocks. For suppose 

 a particular spot to be covered with ice, adhering firmly to the 

 surface. Water, flowing in among the ice, Avould lift up its masses 

 and float them away as icebergs, which would drop then* load of 

 detritus as they melted away, and thus the insidated bowlders 

 and those crowning the ridges of mountains, would be most satis- 

 factorily accounted for. But this action would not account at all 

 for those larger and more numerous bowlders found near to the 

 original rock, nor for that powerful abrasion and furrowing which 

 the unbroken ledges exhibit. These phenomena, however, would 

 be the result of crowding huge masses of ice over the spot. These 



