AGENCY OF THE SEA. 



145 



tinuation of those occurring on the main land, the 

 most cautious reasoner can hardly avoid the con- 

 clusion that such was the origin of this harbour. 

 Nay, it is difficult to see why the same reasoning 

 will not apply to the whole of Massachusetts Bay; 

 and when we see with what tremendous force the 

 ocean must, for ages, have battered the hard syenitic 

 rocks of Cape Ann, and what an immense accumu- 

 lation of sand, gravel, and bowlders has been made 

 aljong the south shore of this bay, we feel almost 

 prepared to adopt this theory," &c. 



Lieutenant Mather, geologist to the first district 

 of the State of New-York, thus speaks of the en- 

 croachments of the sea upon the shores of Long 

 Island : 



" Vast masses of the cliffs of loam, sand, gravel, 

 and loose rocks, of which Long Island is compo- 

 sed, are undermined and washed away by every 

 storm. The water on the ocean coast, to some dis- 

 tance from the shore, is almost always found to 

 have more or less earthy matter in suspension, 

 much of which, except during storms, is derived 

 from the grinding up of the pebbles, gravel, and 

 sand, by the action of the surf. This earthy matter 

 is carried off during the flood tide, and in part de- 

 posited in the marshes and bays, and the remainder 

 is transported seaward during the ebb, and deposited 

 in still water. After a close observation, I have es- 

 timated that at least 1000 tons of matter is thus 

 transported daily from the coast of Long Island, and 

 probably that quantity, on an average, is daily re- 

 moved from the south coast, between Montauk 

 Point and Nepeaque Beach. This shore of 15 miles 

 in length probably averages 60 feet in height, and 

 is rapidly washing away. 1000 tons of this earth 

 would be equal to about one square rod of ground, 

 with a depth of 60 feet. Allowing this estimate to 

 be within the proper limits, more than two acres 

 would be removed annually from this portion of 

 M 



