496 The Formation of Cape Cod. [ August, 
Nantucket is almost wholly composed of stratified gravel and 
sand. Along the whole south side of the island, from Long pond 
to Tom Never’s Head, these lie in nearly level plains, twenty to 
sixty feet above the sea. This expanse, reaching more than ten 
miles from west to east, with a width varying from one to three 
miles, is broken by frequent hollows which extend approximately 
from north to south like those already noticed on Martha’s Vine- 
yard. Narrow ponds, of the same height as the ocean, fill the 
entire course of these depressions, or occupy their lower end 
next to the beach. All the ponds along the south shore are of 
this class, including Long, Hummock, Miacomet, Weweeder, 
Nobadeer, Madequecham, Wigwam and Forked ponds, with sev- 
eral others of smaller size. The line at which the ice-sheet 
appears to have terminated is marked in the west part of the 
island by gently undulating hills, forty to fifty feet high, com- 
posed of stratified drift, which, however, differs from that of the 
plains in having here and there boulders up to ten feet in diame- 
ter embedded in it or lying on the surface. The course of this 
line is from Eel point, north of Maddequet harbor, by Trot’s 
hills, to the town. Eastward it continues on the same course in 
the Shawkemo hills and Saul’s hills to Sankaty Head. The por- 
tion of this series called Saul’s hills, two miles long and a half mile 
wide, is of very irregular contour, with steep and abruptly- 
changing slopes, forming hills, ridges, mounds and small enclosed 
basins, some of which contain ponds. The material is stratified 
gravel and sand, upon and in which are scattered boulders, vary- 
ing up to ten feet in diameter. 
Sankaty Head, at the east shore of the island, affords a section 
across this range! A quarter of a mile south from the light- 
house, the order of deposits, beginning at the base, is as fol- 
lows: brown sandy clay to about twenty feet above the sea; 
ferruginous sand and gravel, four feet; white sand, four feet; 
yellow sand, enclosing masses of biua clay, one foot; ferru: 
ginous gravel and sand, with abundant shells, two feet; a bed 
of Serpulæ mixed with sand, about two feet; gravel and sand 
again, thickly filled with shells, two feet; fine white sand, 
about ten feet; the common yellow sand and fine gravel of the 
modified drift, about forty-five feet, its top being at ninety feet; 
‘The Post-pliocene beds at the base of this section, and their fossils, are fully 
z described by Prof. A. E. Verrill and Mr. S. H. Scudder, in the American Journal 
is Y Science TE 3d series, Vol. X, pp. 364-375. 
