GRANITE OF NORTHERN AQUIDNECK. 273 



about N.-S., or a little west of north. In consequence of the breccia- 

 tion the rock often has a decidedly conglomeratic appearance. Where 

 shearing- has taken place the pebble-like fragments usually remain light in 

 color and the cementing material is darker. In other places the fragments 

 are very dark in color and seem macroscopically to be full of hornblende 

 and black mica. These dark fragments resemble closely the so-called dark 

 or hornblendic schists of the Sin and Flesh Brook section, while the light- 

 colored rocks resemble the lighter so-called quartzitic schists of that section. 

 A pinkish aplite cuts the rock near the southeast end of Gould Island in 

 the form of narrow dikes. 



GRANITE AREA OF THE NORTHEAST END OF AQUIDNECK 



ISLAND. 



Whitish granite occurs along the southern margin of Hummock Point, 

 and reddish granite is found along the east shore farther north. A pinkish 

 aplite cuts the same. Whitish granite forms a hill extending north of 

 Hummock Point as far as the railroad. The granite is frequently sheared 

 in a north-south direction, the result varying from a gneissoid granite 

 to a black mica-schist. Half a mile north of the railroad another set of 

 ridg-es begins, extending northward. It consists of whitish granite, sheared 

 in a direction west of north, often N. 20° W. One result of the shearing 

 is again a gneissoid structure, varying to a black mica-schist. Associated 

 with the granite toward the middle and northward is the fine-grained 

 quartzitic rock already described as occurring with the granite northeast 

 of the railroad bridge at Tiverton, and also as occurring in the Sin and 

 Flesh Brook exposures. Some of the Gould Island rock is also very 

 similar in character to the whitish rock at the northeast end of Aquidneck 

 Island, the whiter rock being probably identical in the two places. At 

 Common Fence Point occurs a reddish granite, not gneissoid. 



The rocks exposed from Gould Island to Common Fence Point are 

 evidently pre-Carboniferous, and belong to the same series as the Sin and 

 Flesh Brook exposures, and that northeast of the Tiverton railroad bridge 

 on the hillside. The Carboniferous exposures on the hillside northeast of 

 Tiverton are noteworthy, suggesting that the eastern border of the Carbon- 

 iferous area extends southward toward the stone bridge. Possiblv this 



mon xxxiii 18 



