6o SEA AND LAND 



are formed, as most pebbles are — by glacial action — are much 

 more irregular in shape, generally being many-sided with the 

 anMes somewhat rounded. Even the pebbles made by the 

 torrents of elevated countries differ in character from those 

 produced by wave or ice action. 



The student who would make a study of sea-beaches, a 

 task to which the would-be geologist may well give a long 

 summer vacation, cannot do better than to resort to eastern 

 Massachusetts, planning his work so that he may travel on 

 foot froni Newburyport to Wood's lloll. In this journey, 

 which, with the detours required by the fretted character of 

 the coast-line, will extend to about three hundred miles, he 

 will fmd fairly good types of all the coastal conditions pre- 

 sented by the Atlantic shore-line south of Greenland and 

 north of Florida. It is true that he will not have very good 

 specimens of fiords, nor of the superb marshes which are 

 offered by the savannas of the Georgia coast, but such feat- 

 ures as straight beaches will be well shown about the Ipswich 

 River, excellent dune phenomena may be found in Essex and 

 about Provincetown, pocket-beaches abound on Cape Ann and 

 along the shores of Boston Harbor, and Cape Cod exhibits at 

 Provincetown and elsewhere beautiful examples of hooked 

 spits. Marine marshes are beautifully shown behind Plum 

 Island lieach and Revere Beach, while the improved area of 

 the same nature in Marshfield shows the steps by which such 

 areas may be won to agriculture, and something of the profit 

 which may be thus attained. At other points on Cape Cod 

 the conversion of the marshes into cranberry bog exhibits an 

 interesting type of agriculture, one w^hich is peculiar to this 

 country. 



As we pass from the northern portion of the Atlantic 



