CAPE COD GEOLOGY 



311 



at the east end of Naushon, near the dwellings of the late Commodore Forbes. 

 These boulders may represent the Montauk till, or one of the lower boulder 

 beds encountered on Marthas Vineyard. The entire assemblage of gravel and 

 coarse and fine sand that appear above sea level in small exposures in the central 

 and western parts of the island closely resembles the Manhasset formation and 

 the underlying Jacob sand. On the east side of Ram's Head, the west chop of 

 Kettle Cove, a bed of fine sand that dips westward is exposed. Similar beds of 

 sand may be seen in broad, wind-bared exposures in the interior of the island, 

 in the "sheep pasture" northeast of Tarpaulin Cove, and in the depression 

 between Tarpaulin and Kettle coves, on the northwest side of the island. 



LATE WISCONSIN OR FALMOUTH MORAINE 



FRONTAL MORAINE 



The frontal moraine on the Elizabeth Islands is an extension of the Fal- 

 mouth moraine in the frontal outcurved lobate margin of the ice lobe that 

 deployed over Buzzards Bay. As seen in the few exposures along the shore and 

 at places in the interior of Naushon the material of this moraine is very thin. 

 In these exposures beds of till 3 or 4 feet thick overlie beds of fine sand. At 

 many places in the interior of the island the later Wisconsin drift appears as 

 isolated boulders resting in the sand or as morainal belts of boulders that 

 dominate the surface. 



The large ridges in the relief of Naushon, which run nearly parallel to its 

 long axis, have a decidedly morainal aspect, but the topography as a whole 

 suggests that they originated as much by the deformation of the older Pleistocene 

 beds as by direct erosion or by being mantled by new deposits during the last 

 ice invasion. Here and there downward slopes that form vales which widen 

 toward the sea suggest the action of running water, such as is evident on Marthas 

 Vineyard and other islands of the outer group, during the interglacial stage 

 preceding the Wisconsin glacial advance. The most conclusive evidence that 

 an ice front extended along the axis of Naushon is seen in the numerous small 

 ridges of boulders and bouldery drift at places on the island where the removal 

 of the forest has exposed the surface to view. In the "sheep pasture" on the 

 hills about a mile or more northeast of Tarpaulin Cove, where the Wisconsin 

 drift forms a relatively thin veneer over Pleistocene yellowish sand, the moraine 

 rises into low, somewhat inosculating bouldery ridges containing scattered large 

 boulders. (See Plate 38, fig. 1.) 



The island appears to be a broad, low ridge, which rises rather steeply 



