CAPE COD GEOLOGY 



171 



remnants of the earlier Pleistocene and Cretaceous beds. The clay is found 

 under the Vineyard Sound margin of the western area and is exposed at many 

 places along the shore. Later action of the ice has undoubtedly removed the 

 clay from some places where it was originally deposited and has thickened it 

 in others, but as it was deposited on the lowlands of that time it was to some 

 extent protected by the remnants of older formations that stood at a higher level. 

 Along the southwestern margin of the western area the clay is not so well 

 exposed, except in Nashaquitsa cliffs. Northeast of these cliffs the outwash gravel 

 and morainal material cover nearly all places where the clay might be expected. 

 However, the clay probably lies along the southeast side of the morainal region 

 and flanks the earlier deposits there in much the same way as it does along the 

 northwest side. 



Outcrops 



In Gay Head cliffs the Gardiners clay is conspicuously absent except at 

 their north end. The only other clear exposure in the town of Gay Head is 

 along the west shore of Menemsha Pond, where the clay is seen at the base of 

 low cliffs, slightly above the level of high tide. Other doubtful exposures can 

 be seen in the eastern part of the town, along the state road. 



The clay is found at places along the south shore of Menemsha Pond. The 

 exposures are the same as those along the west shore. In both localities the clay 

 is overlain by the Manhasset formation. 



In an anticline near the center of the section seen in the cliffs at Squibnocket 

 the Gardiners clay is exposed for a short distance below the Manhasset. 



The Gardiners clay is one of the most conspicuous beds in Nashaquitsa 

 cliffs. It occupies a large part of the section, which affords the best exposure 

 of this formation on the island, for both the top and the bottom of the bed 

 are seen, as well as its folded and overthrust structure and its local thickening 

 due to compression. (See Fig. 11.) West of these cliffs the clay apparently 

 lies below sea level, but here it rises as high as 100 feet above the beach and 

 shows several gentle folds and some overthrusts. One long section of the cliffs 

 is made up entirely of Gardiners clay, but farther east the bed is abruptly broken 

 off and the remainder of the section, except two short stretches, reveals only 

 older beds. 



Along the shore of Vineyard Sound, between Menemsha Creek and Norton 

 Point, there are several exposures of Gardiners clay. The first of these, begin- 

 ning at the southwest end, occurs west of Prospect Hill. Here the clay is gently 

 folded and is overlain by the Jacob sand and Manhasset formation. About 



