SHORES OF THE OCEAN. 85 



with the energy of these agencies. And whoever has examined the surface of the 

 northern parts of this continent with a geological eye, cannot doubt that he has 

 before him examples of their former operation. If the glacial phenomena that now 

 exist in the northern part of Greenland, as they are described in the works of Dr. 

 Kane, once existed here, they would satisfactorily explain the drift exhibitions of 

 North America. 



The ice floods in mountain torrents, above alluded to, possess a power in 

 the removal of detritus, second only to glaciers and ice floes. These several 

 agencies are indeed very similar. For a glacier seems to be only a river of ice 

 urged forward mainly by the force of gravity, aided slightly, perhaps, by the freez- 

 ing of water in the crevices. I have sometimes seen a mountain stream in New 

 England, crowded with blocks of ice so wedged together, that I have safely walked 

 over its surface ; and yet the mass was slowly in motion, and it closely resembled 

 a glacier, even in its erosive power. That of glaciers we know to be still greater ; 

 nor can that of large icebergs, when they plough upon the bottom of the ocean, be 

 less, but in some cases it must be greater. 



To these agents of erosion, perhaps, I should add those of heat and gravity, and 

 the action of plants and animals upon the rocks. But the first two are implied in 

 the agencies already named; and the two latter are so limited in their action, as 

 hardly to need description in this place. 



Conjoined Results of these Agencies. 



They have sometimes acted together and sometimes successively upon the same 

 surface : and sometimes the latest action has obliterated the previous-ones. But 

 the final results we can trace in the following phenomena. 



1. In the Character of the present Shores of the Ocean. 



This presents two phases. The first consists of the beaches, bars, hooks, and 

 shoals of loose materials which the breakers, tides, and currents, have worn off, 

 sorted, and deposited. In some places the projecting shores of unconsolidated 

 materials have wasted away over a wide surface, while in others the sand-banks 

 have been extended a great distance. The encroachments upon the solid rocks, 

 that project into the waters, is less obvious during the life of man; but in many 

 places it is constant, and, therefore, in the course of ages must be very great. 



The other phase of oceanic action, is exhibited in the fiords that are found fre- 

 quently along the coast. These consist of narrow friths that run up between 

 narrow headlands, as in Sweden and Norway, and along the coast of Maine, in this 

 country. It is easy to see that they have resulted from an alternation of harder 

 and softer strata, on the latter of which the sea has operated more effectually than 

 upon the former, aided sometimes by the drift agency. The extent to which this 

 action has been carried on in many places, is truly surprising, and indicates a vast 

 period of time for its accomplishment. Along the coast of Massachusetts, for in- 

 stance, where we see that Cape Ann and the rocks of Cohasset consist of unyielding 



