166 



CAPE COD GEOLOGY 



the upper part of which has a greenish cast. At its base this material consists 

 of coarser feldspathic sand containing shark teeth, phosphatic nodules, and 

 fragments of lignite. The organic remains appear to have been reworked and are 

 derived entirely from Tertiary and earlier strata. The bed has been so much 

 disturbed that it is now upturned into a nearly vertical position. This is the 

 Weyquosque formation of Woodworth. 



Note by J. B. Woodworth: In July, 1920 my attention was called to an opening in a gravel knoll 

 on the land of Mr. Ernest Flanders, in Chilmark, about three-fourths of a mile south of the North 

 Road and half a mile west of Menemsha Pond. This opening exposed Weyquosque gravels containing 

 shark teeth, waterworn pieces of cetacean bone, phosphatic nodules, and some Miocene greensand, a 

 mixture of glacial gravel and organic debris from the Aquinnah or osseous conglomerate and the Miocene 

 greensand. The red sandy ground west of the opening and along the shore of the pond appears to be 

 a broad outcrop of the Jacob sand. On the shore south of Mr. Arthur A. Brigham's land outcrops of the 

 Montauk till form the higher bluffs. 



Moshup till member of Jameco formation and overlying beds. — Above the 

 lowest Pleistocene (Weyquosque) gravel, and separated from it by an un- 

 conformity, is a conspicuous bed of till containing boulders, some as much as 

 8 feet in diameter, embedded in a stony clay matrix. Boulders that were once 

 a part of this bed but that fell out of it because of the removal of the matrix 

 by the waves form a small point on the beach known as Boulder Point. The 

 former extent of the bed is marked by a train of boulders that extends out into 

 the water. The contact between this boulder bed and the lower Pleistocene 

 (Weyquosque) gravel is nearly vertical, and the boulder bed itself stands in a 

 vertical position. This bed, unlike the bed of gravel below it, contains clay and 

 boulders. These beds therefore resemble the Pleistocene beds in Gay Head, 

 where a bed of stony blue clay simulates a deposit of till, but the stony blue 

 clay in the Gay Head section is regarded by Professor Woodworth as an older 

 deposit, of Mannetto age. The stratigraphic relations here are described more 

 fully by Professor Woodworth. The positions of the beds both in Nashaquitsa 

 cliffs and in Gay Head indicate a vigorous ice advance before the deposition 

 of the Gardiners clay. 



Against this conspicuous boulder bed rests the Gardiners clay, but obviously 

 not as it was originally laid down, for it is folded in small plications, which in- 

 dicate that it has been thrust against the boulder bed, probably by later ice 

 action, and possibly that which deposited the Montauk till and forced the 

 plastic clay against this resistant bed of boulders. The typical Jameco type of 

 gravel is not exposed here, but it may be concealed by the beach. Professor 

 Woodworth regards the Moshup till as the correlative of at least the upper 

 part of the Jameco gravel of Long Island. 



