358 GEOLOGY OF THE NAERAGANSETT BASIN. 



at Slate Hill and southwestward. The exposed portion of the shales 

 beneath the conglomerates at Eastons Point adds up, according to Prof. 

 T. Nelson Dale, to at least 600 feet, with an unknown thickness of shales 

 beneath, but even the shales exposed can not all be called green. The 

 thickness of the upper green shales must occasionally equal 200 to 250 feet. 



THICKNESS OF THE SAKONNET SANDSTONES. 



The upper sandstones and shales beneath the conglomerates at Black 

 Point have a thickness of at least 110 feet, while their total thickness at this 

 point is evidently greater. The corresponding series at Taggarts Ferry 

 can, however, hardly exceed that amount. Their thickness east of the river 

 is discussed later. 



The thickness of the more typical dark-blue Aquidneck shales probably 

 exceeds 3,000 feet, The upper green shales and the Sakonnet sandstones 

 do not add considerably to this thickness, so that an estimate of 3,000 to 

 3,500 feet for the Aquidneck shale series seems reasonable Desirable as it 

 would be to secure a better idea of the total thickness of the Aquidneck 

 shales, this is at present impossible. The accessible data do not furnish the 

 means for such an estimate. 



NORTHERN EXTENSION OF THE AQUIDNECK SHALES. 



North of Bristol Neck the Aquidneck shale series seems to lose its 

 identity. Greenish-blue shales continue to be exposed at several points a 

 mile north of the Warren and Fall River Railroad, but on continuing north- 

 ward are soon intercalated with sandstones and conglomerates to such an 

 extent that they can no longer be recognized as a distinct series, but 

 evidently merge northward into the upper part of Mr. Woodwortk's lower 

 Coal Measures series. 



EQUIVALENTS OF THE KINGSTOWN SANDSTONE AND AQUIDNECK 

 SHALE SERIES NORTHEAST OF WARREN NECK. 



East of Aquidneck Island and Bristol and Warren necks it appears 

 impossible to distinguish between a lower Kingstown sandstone and an 

 upper Aquidneck shale series. Sandstones and shales are exposed below 

 the coarse conglomerates southwest of Swansea village. Coaly shales are 



