WARWICK AND SOUTHERN CRANSTON. 257 



the Carboniferous, extending along the western border of the Carboniferous 

 field, often presenting workable coals, was well recognized by early investi- 

 gators of this district, many of the mines dating back more than fifty years, 

 though all save one, that at Valley Falls, are now totally abandoned. 



The most southern exposure on the east side of Sockanosset Hill is 

 half a mile south of the State almshouse, near the railroad. The medium- 

 grained sandstone is bluish; the coarser, whitish. Quartz pebbles up to 

 1£ inches in diameter occur in the conglomeratic layers. The series dips 

 10° NE. In front of the almshouse are black ottrelitic shales. Toward 

 the northeastern side of the building, and thence for a rather long distance 

 through the grounds, more sandy bluish sandstones, occasionally conglom- 

 eratic, occur, merging into fine-grained rocks, and these into g-reenish and 

 bluish shales, in part ottrelitic. The strike of the series is north-south, car- 

 ry ing the rocks east of the Reform School. The dip is 20° E. The finer- 

 grained rocks and shales rather predominate in this series, and may also be 

 seen near the almshouse, east of the road. In the vicinity of the Reform 

 School and of the reservoir, exposures of bluish sandstone and ottrelitic 

 shales occur. The coaly beds, including the workable coals, occur half- 

 way down the eastern hillside and thence down into the valley region. 

 The strike of the rocks is north-south, the dip low east — usually 20° E. — 

 except toward the mine, where the dip, according to the miners, increases 

 to about 50° E. If this is true, it is a local flexure, the dips eastward being 

 low again. The existence of such a flexure seems, however, to be supported 

 by indications northward, the dip at Wayland Station, on the northwest 

 side of Sockanosset Hill, being 20° to 30° E., while on the eastern side of 

 Rocky Hill it is 40° to 70° E. 



Eastward of the Pawtuxet River, however, the exposures show low 

 dips again. Along the railroad north of Hills Grove Station, black, often 

 coaly, shales lie almost horizontal. North of the road corner east of the 

 station a quarry shows abundant sandstone with a northward dip of about 

 20°. A third of a mile north of the station, west of the railroad, abundant 

 sandstone with conglomeratic layers shows a northeastward dip of 20°. The 

 sandstone contains stems of calamites, longitudinally coarsely corrugated 

 steins, undeterminable flattened stems, and leaf-like impressions, 1 or 2 

 inches wide and 15 to 30 inches long. Similar forms may be recognized 

 mon xxxiii 17 



