262 GEOLOGY OF THE NARRAGANSETT BASIN. 



conglomerate exposures lie green shales of the same type as those belong- 

 ing to the shale series southward. The green shales are exposed chiefly 

 along two low ridges, the first one-third of the distance from the line of 

 the conglomerates to the Warren-Bristol road, and the second about two- 

 thirds of that distance. No strike and dip could be determined. The 

 cleavage is marked and the planes are numerous. Notwithstanding the 

 absence of definite stratification the dip is undoubtedly eastward, corre- 

 sponding to the dip and strike of the rocks below and above. The green 

 shales therefore here overlie a very coarse conglomerate, but the conglom- 

 erate seems to have had but a very limited extension. Overlying the bluish- 

 green shale is a bluish sandstone bed, the lowest part of which is conglom- 

 eratic, the pebbles being of small size. The exposure occurs east of those 

 last mentioned, east of the Bristol-Warren road, and forms the summit of 

 the hill. The strike can not be well determined, but seems to be about 

 N. 45° W., dip 45° E. Eastward the sandstone becomes rapidly less coarse, 

 then very fine grained, and is finally overlain by the bluish shale which 

 forms the exposures over the remainder of the area of the neck north of 

 the pre-Carboniferous granite region. This shale is well exposed west of 

 the road half a mile farther northward, east of the road in the valley, and 

 along the entire western margin of the hill just beyond for half a mile 

 southward. It is also exposed near the summit and along the northern 

 and northeastern sides of this hill, which may be recognized by its height 

 of 120 feet, as indicated on the map. At the second angle of the road 

 toward the northeast of the hill the shale is very black and carbonaceous. 

 Farther eastward, east of another main north-south road, the greenish-blue 

 shale is again abundantly exposed directly east of the summit of the 120- 

 foot hill. The shale is also well exposed in quarries and on the hillside 

 less than a mile farther northward on the eastern side of the hill, near the 

 top. In all this area, excepting in the cases already described, the Carbon- 

 iferous is represented by the shale series, varying from bluish green to 

 greenish and bluish, sometimes dark blue and black. 



GRANITE AREA. 



Granite occupies the southern part of Bristol Neck. A coal bed was 

 once exposed in the western part of Bristol only a few feet above the 

 harbor. It was said to strike east of north and to dip about 48° W. The 



