OF CREATION. 325 



action of gravitation, or by some supposed force con- 

 nected with the alternate thawing and freezing of 

 water, others have assumed that the ice may have 

 acted in the form of icebergs. In other words, it has 

 been supposed that glaciers, descending to the sea 

 in cold climates, may have been broken off from 

 time to time and floated away, conveyed by marine 

 currents until they are either melted by the warmer 

 waters of the ocean or stranded on some submarine 

 mud -bank or shoal. In either case, and both are 

 illustrated by recent examples, the load of broken 

 rock which such masses of ice carry would form a 

 bed of gravel, which, on subsequent elevation of the 

 sea bottom, might become a portion of the general 

 surface of a continent or island. 



The breaking up of the surface, during or after the 

 intense cold of an Arctic winter, or even of such 

 cold as occurs annually in thickly-inhabited districts 

 in Russia, is another means by which some of the 

 phenomena of gravel when little removed from the 

 parent rock have been explained. Geologists are in- 

 debted to Sir Eoderic Murchison for this and many 

 other ingenious suggestions concerning the origin of 

 gravel ; and there can be no question, that the care- 

 ful examination of existing nature, so far as it is 

 exposed to our view, is the most satisfactory as it 

 is the safest and most reasonable mode of explain- 

 ing the various appearances which are presented in 

 the course of geological investigations. 



Whatever the cause or causes may have been, the 

 distribution of numerous blocks of stone, sometimes 

 rounded, but more frequently angular, and of every 

 size and shape, and the removal of these to various 



