CHAPTER I 



GEOLOGY OF NANTUCKET AND ADJACENT ISLANDS 

 By J. B. Woodworth 



NANTUCKET 

 GEOGRAPHY 



Nantucket, which lies about 25 miles south of the main arm of Cape Cod, 

 is the easternmost of a group of glaciated sandy and clayey islands off the south 

 coast of Massachusetts, Rhode Island, and Connecticut. Although it is low, 

 attaining an elevation of 100 feet above sea level at only one point, it is the third 

 largest island in the group, and it forms a barrier behind which broad sounds 

 afford protected passageways for ships for nearly 200 miles. On its east and 

 southeast sides it is protected from the breakers of the heavy storms of the 

 Atlantic by broad shoals, of which George's Banks, about 90 miles to the east, 

 is the best known. Notwithstanding this protection the islands are encroached 

 upon by the sea, which here and there capriciously adds piles of sand to the 

 coast or as capriciously removes them. 



Nantucket enjoys a wide reputation for its cooling sea breezes in summer 

 and for its oceanic climate throughout the year. Its beds of glacial gravel yield 

 an abundant supply of drinking water, and its excellent sand beaches afford 

 varying exposures to the sea, facing the open Atlantic on its south and east 

 sides and the quieter water of the sound on its north side. The island contains 

 no valuable mineral resources, but the striking waste of its coast through the 

 attack of the sea (see Plate 10, fig. 1) and the fact that it is an instructive part 

 of the great terminal moraine at the latest stage of the glacial ice give it peculiar 

 geologic interest. 



Nantucket appears to have been well wooded before it was occupied by 

 Europeans, but it is now almost treeless. Evidence of the existence of the ancient 

 forest is occasionally seen in fallen trunks of oak found in peat bogs. 1 The pines now 

 growing on the island were set out 60 or 70 years ago, but those that were planted 

 along the coast did not survive the attack of the high winds, and the existence 

 of all the trees was at one time threatened by the pine moth (Retina frustana) . 2 



1 Wilder Burt G., Evidence as to the former existence of large trees on Nantucket Island, Proc. Am. 

 Assoc. Adv. Sci., 40, 1894. 



2 Scudder, Samuel H., The pine moth of Nantucket, Pub. Massachusetts Society for the Promotion of 

 Agriculture, Boston, 1883. 



