(398) 



with the United States Coast Survey, between the years 1846 

 and 1886 (/. c. f 361-363, ^f,g\ 62). 



From the observations recorded there appears to have been 

 a systematic sequence of events in connection with these 



*\ARTHA9 VINEYARD 



Fig. 1. 



changes, due to the fact that the prevailing direction of the 

 shore currents is there from west to east, thus building up 

 and extending the beach at the western side of any opening 

 and forcing the tidal currents over to the eastern side, which 

 is by this means constantly eroded. The opening is thus 

 shifted further and further eastward until it reaches Wasque 

 Point, when it can go no further and finally becomes closed, 

 when a new opening forms at the western end of the beach 

 or this latter may form before the other has ceased to exist. 

 Topographically the island consists of a collection of 

 rounded, irregularly disposed hills, bordered on the south 

 and east by narrow areas of sea beach. The maximum ele- 

 vation is about eighty-five feet, at Sampson's Hill. Steep 

 bluffs, twenty to forty feet high, are exposed at several local- 

 ities along the shores of Katama Bay and Edgartown Harbor 

 and an elevation of forty feet is reached a short distance 

 from the shore, on Cape Poge, but in the eastern portion of 



