l^EWPOET HAEBOE ISLAKBS. 307 



then the strike suddenly becomes N. 80° "W., dip 40^ S., changing to N. 20° 

 W., dip irregularly south, after which carbonaceous shales and sandstones 

 make their appearance, occasionally showing conglomerate, the strike being 

 approximately N.-S., and the dip 45° E. Southward, along the soutliwestern 

 border of the main body of the island, coarse conglomerate is seen again, 

 striking at first N. 40° E., dip 40° to 20° E.; then, as the shore turns southeast, 

 the strike becomes N. 45° W., then N. 10° W., dip low east, the conglom- 

 erate becoming less coarse. Farther southward dips of 80° E. are noticed, 

 and then, as the shore turns southward, green fissile shales, similar to the 

 Conanicut shales, make their appearance. 



At the southwest angle of this tongue of ^the island, arkose with thin 

 layers of carbonaceous shale outcrop, with strike E.-W , dip 40° N. The 

 rock south of the arkose and forming the southern end of the island is 

 a greenish rock, which provisionally is here placed with the Newport Neck 

 series of shales. Near the arkose it strikes N. 30° W., dip 40° E., and east- 

 ward N. 50° W., dip 25° E. Similar arkose is found on Bishop Rock and 

 on Rose Island. 



The coarse conglomerates of Coasters Harbor Island are evidently to 

 be associated with the Miantonomy Hill conglomerate. The occurrence of 

 almost constant eastward dips along the western side of the island is to be 

 emphasized. The discussion as to the relationship of these conglomerates 

 to the green shales at the south end of the island is deferred until the 

 Harbor Islands are taken up. 



nSTEWPOKT HARBOR ISIiAlSTDS. 



In this connection the description of the occurrence of the green shales 

 at the southern end of Coasters Harbor Island should be again noted. Off 

 the shore to the south of the island additional exposures of the green shales 

 occur. They are considered to be of pre-Carboniferous age. 



GULL ROCKS. 



The main rock is occupied by a light-house. The pre-Carboniferous 

 green shale here includes a more sandy, coarser variety of that rock, dipping 

 about 20° N. A short distance southward is another exposure of similar 

 nature, also dipping northward. 



