CAPE COD GEOLOGY 



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ability that Muskeget was once larger than it is now and that it was morainal 

 land analogous to Saul's Hills on Nantucket and resembled the part of Nan- 

 tucket that lies along the line of the outer Wisconsin moraine, which stretched 

 lobewise from the east side of Marthas Vineyard southeastward over the site 

 of Muskeget and Tuckernuck Islands to and beyond Nantucket. 



The geological mapping of Muskeget began with C. H. Hitchcock's map 

 in the Massachusetts Atlas of 1871, where the islet is colored to indicate the 

 presence of "Drift and alluvium." In the map in Shaler's report on the geology 

 of Nantucket, 1 Muskeget is shown as a postglacial deposit but is not mentioned 

 in the text. Dr. Gerrit S. Miller, who visited Muskeget in 1892 and 1893, writes : 



Muskeget is about two miles long and at the widest part about half a mile across. It is 

 broadest at the east end, but toward the west it tapers gradually and irregularly, at the same 

 time bending into an imperfect and shallow crescent, the convexity of which is directed north, 

 toward Nantucket Sound. The southwestern end of the island extends as a slender tongue of 

 sand called South Point and is separated from Smith's Beach by a narrow channel. South 

 Point is exposed to the full force of the tide and waves, and as a result is constantly changing 

 in form. . . . The island is, as Mr. Allen describes it, low and sandy — in fact, a mere dry 

 sand bar, nowhere rising more than fifteen feet above highwater mark. The surface is irregu- 

 larly ridged and furrowed, the general trend of the furrows being nearly east and west, or 

 parallel to the main axis of the island. Some of the deeper hollows contain small freshwater 

 ponds or marshes, and there is a salt marsh at the margin of the cove on the south side, but 

 the island is elsewhere perfectly dry and covered with coarse shifting sand. In spite of its 

 barrenness Muskeget has a varied flora, embracing most of the sand-loving plants found on 

 the coast of southern New England. 2 



Muskeget appears to be a wave-leveled remnant of the terminal moraine. 

 Its antiquity and its long separation from the neighboring islands is indicated 

 by its beach mouse (Microtus breweri Baird), an account of which is given by 

 Miller. This species, which is closely related to a field mouse that is widely 

 distributed on the mainland of New England, appears to have varied from the 

 parent type during its isolation on this island. 



1 The geology of Nantucket, U. S. Geol. Survey, Bull. No. 53, 1889. 



2 Miller, Gerrit S., The beach mouse of Muskeget Island, Proc. Boston Soc. Nat. Hist., 27, pp. 76-77. 



