THIOKNESS AND FOLDING OF KINGSTOWN SERIES. 345 



River. In that case the area involved has a width of at least 10 miles at 

 the northern limit of the Narragansett Bay map. 



The increase in the width of the area occupied by the Kingstown series 

 from 3| miles on the south to 10 miles on the north is of course striking 

 and demands some explanation. 



Thickness of the series and evidence of folding. The tllicklleSS of tile SeHeS Call be 



measured with the greatest degree of certainty at its southern end, where 

 exposures are frequent and dips are steep. The total thickness of 11,500 

 feet there indicated may not equal that of the formation farther northward. 

 The steep dips in the area immediately north of a line connecting Quonset 

 Point, Wickford, and Wickford Junction, for instance, suggest a greater 

 thickness. So does the great east-west extension of the formation 

 northward Unless in spite of the apparent uniformity of strikes and dips 

 over large areas there be in reality a system of repetition due to folding, 

 the thickness of the Kingstown sandstone group must in places greatly 

 exceed 11,500 feet. There is a little evidence in favor of such folding in 

 the portion of this region actually occupied by the Kingstown sandstones: 

 (1) Along the eastern side of Providence River, north of Riverside occurs 

 a synclinal fold, but this seems to disappear northward. (2) At Rumstick 

 Neck and on the southwestern side of the Aquidneck shale area on Bristol 

 Neck the trend of the underlying sandstones suggests synclinal folding. 

 (3) Prudence Island is a case of a well-marked synclinal fold. (4) The 

 steep dips, varying suddenly to lower inclinations, on the northwestern side 

 of Conanicut suggest crumpling of strata and possible folding. (5) The 

 shale area of southern Conanicut has evidently suffered folding, but the 

 character of this folding has not been well worked out. (6) Folds are 

 known in various parts of Aquidneck Island All of these facts sugg-est 

 folding also in the more western area occupied by the Kingstown sandstones, 

 but the direct evidence in favor of such folding is still wanting. 



The view that the thickness of the sandstone series northward probably 

 does not greatly exceed 11,500 feet is also supported by the very low 

 general inclination of the strata over considerable areas, which tends to 

 reduce the estimates made in conformity with regions where the dip is 

 steeper. The very low general dips of most of southwestern Cranston and 

 Warwick have already been mentioned. 



The dips on the western side of Bristol Neck are comparatively low. 



