374 GEOLOGY OF THE NARRAGANSETT BASIN. 



being possibly not exposed. The Purgatory-Paradise section of coarse con- 

 glomerate may range between 600 and 450 feet in thickness, according as the 

 lower and eastern one of the two ridges is or is not included in the section. 

 Fossn localities. — Ferns are found in Woods Castle, in a coaly shale which 

 belongs stratigraphically within the coarse conglomerate series. They 

 occur also in the Newport Cliffs a short distance south of Marys Seat, in a 

 coaly black shale about 14 feet thick, overlying a conglomerate bed about 

 11 feet thick, with pebbles often 4 inches thick. Fossil ferns are still more 

 common in the coaly shales southwest of Ochre Point, near the top of the 

 sea wall. The position of these coaly shales is not accurately known. 

 They lie west of the Newport Cliff section with its conglomerates, but may 

 belong to the shale series exposed beneath Newport. This, according to 

 the writer's interpretation, would place them below the coarse conglomerate. 



