172 



CAPE COD GEOLOGY 



half a mile beyond this place the Gardiners clay is exposed in the face of the 

 cliff as if it were nearly horizontal, but in a gully that runs at right angles to the 

 shore it has the form of a close anticline, the upper part of which is exposed 

 along the face of the cliff. A third exposure of the clay is seen immediately west 

 of the mouth of Roaring Brook. Here it has been so much compressed that it 

 is abnormally thick and full of small plications. The clay here was once worked 

 for making bricks, and the remains of the old brickyard are still seen at the 

 mouth of the brook. The clay is here overlain by a thick bed of Manhasset 

 gravel. In one of the gullies at this locality a bed of gravel lies below the Gar- 

 diners clay. The clay here has probably been overthrust on this bed, which 

 resembles the Manhasset and not the pre-Gardiners beds. 



East of the mouth of Roaring Brook the Gardiners clay is exposed in the 

 cliffs more extensively than elsewhere along this coast. It is considerably dis- 

 turbed (see Figure 13) and is overlain by the Jacob sand and the Manhasset for- 



NE sw 



Fig. 13. — Section, on the shore northeast of Roaring Brook. A, Gardiners clay; B, Jacob sand; C, 

 Herod gravel; D, Montauk till; E, Hempstead gravel ; F, Wisconsin till. The Herod, Montauk, and 

 Hempstead are members of the Manhasset formation. 



mation. Northeast of this locality, as far as the section between Lambert's Cove 

 and Norton Point, the Gardiners clay is not exposed, and only a small amount 

 of clay can be seen at either of these two places. At Norton Point the clay 

 overlies unconformably a bed of old till. The relation between these two beds 

 at Norton Point is one of the best evidences as to the age of the till. (See fig. 

 12.) The overlying beds are again the Jacob sand and the Manhasset formation. 

 About a quarter of a mile southwest of the small long pond between Chappa- 

 quonsett and James ponds, and again southeast of it, there are small old pits 

 from which clay was once dug. This clay is said to have burned red and prob- 

 ably the Gardiners is a red-burning clay. The place where it occurs is not one 

 where it would be expected, and the deposit stands at a much higher elevation 

 than any other known bed of the Gardiners clay. 



Form of Surface 

 Large lenses of the Gardiners clay have been variously distorted by the 

 action of the Montauk ice, so that their surfaces vary from nearly flat to sharply 

 ridged, the ridges having been caused by anticlinal folding. The amount of dis- 



