Gain of the Land upon the Sea. 



120 



Sandy Neck extends eastward from Sandwieh nearly across Barn- 

 stable harbor, and it continues to advance in an easterly direction. 

 There can be little doubt, also, that nearly, or quite the whole of 

 Provincetown was formed in the same manner, and ought to be re- 

 garded as alluvial. 



In like manner Smith's Point, which is a low sand beach constitut- 

 ing the southwestern extremity of Nantucket, has been produced by 

 materials drifted thither by tides and currents from the eastern side 

 of the island. When Des Barres constructed his chart, its extent was 

 nearly the same as at present. But since that time, as Lt. Prescott 

 informs me, it has been from one to two miles shorter. Whether the 

 current that forms this beach passes around the northern point of the 

 island, or along its southern shore, has not been ascertained : but it is 

 certain that a current does set around the northern point, and thence 

 along the northwestern shore, as certain facts prove, which I r have 

 not time to mention. And probably it is this current chiefly which 

 has formed Smith's Point; and not unlikely, also, the islands of 

 Thuckanuck and Muskegut, as well as the extensive shoals between 

 Nantucket and Martha 1 s Vineyard. It may be likewise, that another 

 current passes along the south shore of Nantucket, aiding in this 

 work, and forming Nantucket Shoals. And perhaps the irregular 

 action of these currents, aided by unequal tides, may sometimes 

 lengthen out, and at other times curtail the low beach of Nantucket 

 called Smith's Point. 



In several other places on the shores of Nantucket, there appears 

 to have been an accession to the land, in the manner that has been 

 described. But I am too ignorant of details concerning these spots, 

 to be able to make any statements of interest about their progress or 

 extent. 



Considerations like the foregoing often lead a man to feel as if such 

 low sandy islands as Nantucket, and others in its neighborhood, were 

 sliding from under his feet. But that no general change of position 

 has taken place in them is obvious from the fact, that most of the cliffs 

 on the shores of Nantucket at least, exhibit regular layers of sand 

 and clay, demonstrating its general structure to be that of a tertiary 

 formation, which has never been removed since its original deposi- 

 tion. True, if the world exist long enough, and these agencies con- 

 tinue to operate, the whole island will change its position. But as 

 the work has progressed so slowly during the past 6000 years, the 

 time requisite for its completion must be immensely great 

 17 



