CHAPTER VII. 



THE KINGSTOWN SERIES. 



Unity and iithological character of the Kingstown sandstone series. At tile present Sta^e 



of investigation it does not seem feasible to separate the Carboniferous 

 strata lying along the western border of Narragansett Bay, between East 

 Greenwich, and Narragansett Pier, into divisions of geological value. No 

 fossils have so far been discovered in them. Lithologically they consist of 

 frequent alternations of the following rocks: 



First. A coarse quartzitic sandstone, almost an arkose, evidently derived 

 in large part from some earlier granite area. This sandstone frequently 

 contains flakes of white mica, or of biotite and some other dark mineral. 

 The color of the sandstone in general is white, the quartzitic elements very 

 much predominating. 



Second. As this sandstone becomes coarser it contains, at first, scattered 

 quartzite pebbles, and then thin layers of a conglomeratic nature, merging 

 into time conglomerates a few feet in thickness, the jjebbles of which usually 

 consist of quartzite, occasionally of granite, and, except in a few localities, 

 do not exceed an inch or one inch and a half in diameter. 



Third. As this sandstone becomes finer it also turns darker, the varia- 

 tion in color being usually due to an increase in the amount of carbonaceous 

 material. In some of the more northern localities, however, the coarser and 

 medium-grained sandstones are of a bluish color, which appears to be due 

 to a decrease in the quantity of carbonaceous matter, making more evident 

 the dissemination of iron in some form throughout the rock. The blue 

 color is usually, in the case of the less carbonaceous sandstones, a sign of 

 less metamorphism. During metamorphism the ferruginous matter seems to 

 have collected partly in the form of magnetite and partly as a constituent of 

 black mica, leaving the general mass of the rock whitish, but flecked with 

 black specks. 



Fourth. The medium-grained sandstones merge into a very fine-grained 



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