248 GEOLOGY OF THE NARRAGANSETT BASIN. 



FROM 8AUNDERSTOWN TO WICKFORD. 



North of Saunderstown the same series occurs that is exposed along the 

 shore from Saunderstown to Narragansett Pier. Except for a short distance 

 between Caseys and Greenes points the exposures are all confined to the 

 more inland districts. Most of the outcrops are sandstones. The softer, 

 more finely grained, and more carbonaceous sandstones, almost possessing 

 the character of shales, are more rarely seen than south of Saunderstown. 

 This may mean that unequal erosion has left their former line of outcrop 

 beneath the present level of the soil, or that they were rarer in the area 

 northwest of Saunderstown. The facts noted in the field point rather to a 

 diminution in the frequency of the darker, shaly strata. The rocks corre- 

 sponding best to the shale seem to be less carbonaceous than southward, 

 and merge into fine-grained sandstones only sufficiently carbonaceous to 

 give them a very dark, but rarely a really black, color. 



Where first exposed north of Caseys Point, the dip of the sandstone 

 is about vertical. At the beginning of the continuous exposures the strike 

 is N. 6° E., dip 35° E. The coarser sandstone is very quartzitic, white, 

 with abundant white mica, spotted with a more scattered black micaceous 

 mineral. The cross stratification is often marked (PI. XX). This sandstone 

 contains frequent thin conglomeratic layers, with pebbles up to 1^ or 2 

 inches in diameter. The pebbles are usually quartzitic, occasionally gran- 

 itic. Interbedded with these rocks are darker, more carbonaceous, finer- 

 grained courses. Going northward toward the quarry a rather thick layer, 

 more carbonaceous than usual in this more northern area, borders the 

 shore. Here the strike is N. 10° W., dip 45° E. A pegmatite dike cuts 

 the rock parallel to the strike. A darker, finer-grained, more ferruginous 

 dike also seems to occur. The alternation of finer-grained, more carbon- 

 aceous rock, coarser white sandstones, and occasional thin pebble layers 

 continues as far as Hazzard's quarry. Here the strike is N.° 8 E., dip 

 perhaps 60° E. 



From this quarry westward, as far as the angle in the road connecting 

 Saunderstown and Hamilton, there are a number of good exposures on the 

 hillside. The large exposure at the quarry consists almost entirely of white 

 sandstone. At the house on the hillside there occur wide layers of a dark- 

 blue, very fine-grained shaly rock, which takes the place of the much more 



