V 



in Massachusetts. 75 



that the diluvium had been washed away from these 

 islands, did we not actually detect the process. But at 

 the Great Brewster, the work is going on before our eyes. 

 Its eastern or outer side is a nearly perpendicular bank of 

 diluvium, obviously wasting away by the action of the 

 waves, that roll in upon it from the wide Atlantic ; while 

 the extensive beach, stretching away from its southern 

 point in a westerly direction, is composed of materials 

 swept from its eastern shore. Several other islands 

 exhibit a similar process on their Atlantic shores. Can 

 we doubt, then, that all the outer and rocky islands have 

 been deprived of their coat of gravel and sand by a simi- 

 lar process ? Whether the whole space between the 

 Great Brewster and the outermost of the Graves, which 

 is not less than two and a half miles, was once occupied 

 by diluvium, cannot be certainly determined ; though 

 very probable. Indeed^ when one passes along the south 

 shore of Massachusetts Bay, and finds nearly the whole 

 of Plymouth and Barnstable counties made up mostly of 

 the iiragments of such rocks as are found in Essex and 

 Suffolk counties, will he not be led to ask whether the 

 whole of Boston harbor, and even most of Massachusetts 

 Bay, may not have been produced by the long continued 

 action of the waves, urged on by a northeast wind, and 

 accelerated, perhaps, by diluvial agency? True, the 

 mind Is staggered in attempting to conceive of the im- 

 mense period requisite for such a work by existing agen- 

 cies, operating with no greater intensity than at present. 

 But the geologist, who means correctly to appreciate the 

 ges which our globe has undergone, must prepare 

 himself to admit many such periods for their accomplish- 

 ment, even if he admit an occasional increase of intensity 

 in their causes. 



an 



