328 GEOLOGY OF THE NARRAGANSETT BASIN. 



also on tne southwest and northeast sides of the hill immediately northward, 

 and again, for the last time, a quarter of a mile northward, west of the road. 

 The green shales therefore form a series overlying the bluish-black 

 shales, although evidently a part of the same and representing only the 

 upper courses of the series. 



PORTSMOUTH CONGLOMERATES. 



A road leads from Portsmouth Grove Station eastward to the Newport 

 road. An eighth of a mile southeast of the road corners conglomerate 

 with quartzitic pebbles Up to 10 inches in diameter is found. The trend of 

 the exposures is about N. 10° to 15° E., but the strike and dip could 

 not be satisfactorily determined. Northward, the same distance northeast 

 of the road corners, bluish sandstone, varying to green, in places coarse, 

 and with some layers of fine conglomerate, is seen. The trend of the 

 exposures is N. 12° E. A quarter of a mile northeast of the crossroads 

 the greenish slate is seen on the hillside nearer the Newport road, becom- 

 ing more bluish eastward and merging - into a more sandy rock toward the 

 northeast, where it is more nearly in line with the previous exposure. 

 Three-quarters of a mile from the crossroads, along the top of the hill, 

 considerable sandstone occurs. It includes a narrow greenish shale layer, 

 and at the southwest end a few thin conglomeratic beds, with pebbles not 

 exceeding half an inch in diameter. An eighth of a mile northeastward, 

 and the same distance from the next east-west road, greenish-blue shale 

 again occurs westward, with gray sandstone eastward. A few layers 

 are coarse, almost conglomeratic. North of the east-west road loose 

 pebbles, similar to those usually found in conglomerates, occur with con- 

 siderable frequency on the east side of the hill, east of the regular green 

 shale exposures of the hill. Over three-fourths of a mile northward, an 

 eighth of a mile northeast of the crossroads, begins a ridge extending 

 N. 80° E., across the next road leading northward. This ridge is formed in 

 the main of conglomerate, composed of quartzitic pebbles often 8 inches 

 or longer in diameter, and containing fossil oboli. The conglomerate 

 strikes N. 20° E.; the dips are difficult to determine, but seem to be in some 

 places nearly vertical, in others less steep. A greenish-blue shale bed is 

 apparently interbedded in places. This ridge of conglomerate lies half a 

 mile a little west of south of Butts Hill, and, like the shales of that hill, is 



