FOSSILS OF AQUIDNECK SHALES. 363 



formations farther south is sufficiently marked to warrant their separation 

 in this part of the report. 



It is not impossible that the Kingstown series is not at all exposed east 

 of the Eastern Passage. The section between the coarse conglomerates 

 and the basal arkoses is evidently much smaller there than on the western 

 side of the bay, and no exposures assignable to the Kingstown series are in 

 direct evidence. 



The Aquidneck shales on the southwestern margin of Prudence Island 

 have weathered in an irregular manner, producing many small cavities 

 upon the surface of the shales, giving the appearance of irregular fretwork 

 (PL XXIV). 



FOSSILS OF THE AQUIDIS^CK SHALE SERIES. 



Fossils are found in the Aquidneck shales at various horizons. The 

 fossiliferous horizon at their very base has already been mentioned — for 

 instance, in the case of the coaly shale on the western shore of southern 

 Prudence Island. The western Portsmouth mine exposures of northern 

 Aquidneck possibly represent a somewhat higher horizon, fern impressions, 

 calamites, and Sigillaria occurring there. Next comes the fern locality near 

 the termination of Corys Lane, on the western shore of the island; then 

 the locality just east of the railroad in the gully half a mile north of Law- 

 tons Valley, where a few ferns were found; next, a mile southeast of Carrs 

 Point, on the western Newport-Bristol Ferry road. The fern impressions 

 found half a mile south of the wharf on the eastern Portsmouth shore, and 

 those found a short distance north of the Grlen, may belong to about the 

 same horizon. The fern impressions found along the roadside three-fourths 

 of a mile northeast of Butts Hill probably represent a higher horizon. 

 Those at the northern side of the Old Fort, on the side north of Butts Hill, 

 are still higher in the series. If the conglomerates at Coddington Point 

 belong to the group of coarse conglomerates overlying the Aquidneck 

 shales, the fern impressions near the northern end of the point represent a 

 horizon above their base. The fern locality along the coast a mile and a half 

 north of Coddington Point at present can not be well located stratigraph- 

 ically. The same statement applies with greater force to the fern locality 

 on the western side of Braytons Point, which consists of coaly shales, such 

 as exist near the top of the sandstone series in the more western parts of the 

 bay region, but the precise stratigraphic position of the deposit is unknown. 



