POETSMOUTH MINE. 321 



Section north of Corys Lane — Continued. 



Feet- 



Black coaly shale i 



Sandstone 10 



Coaly bed, with low eastward dip 20 



Black coaly shale 4 



Black shale and very tine-grained sandstone, with low eastward dip (about 10°), 



showing abundant traces of plant remains 9 



Fine-grained sandstone 4 



Coaly shale and tine-grained sandy rock, striking about parallel to the shore and 



dipping 20° E 8 



Coaly shale - 17 



Black shale, dipping 10° to 15° E 15 



Not exposed 5 



Shaly sandy rock 1 



Coaly shale 9 



The section terminates a little over half a mile south of Portsmouth 

 Mine Station, south of the mouth of the creek. 



PORTSMOUTH MINE AND NORTHEASTWARD. 



At the Portsmouth mine (see footnote on page 381) three beds of 

 coal were formerly mined. The dip was about 35° SE., the strike having 

 changed here considerably toward the east. The old dump shows coal, 

 black shaly slate, and black sandstone, sheared until a part of this is also 

 schistose. Calamites, Annularia longifolia, and many fern-leaf impressions 

 occur here. 



Three-quarters of a mile northeastward, on the hillside east of the 

 railroad, a coal seam was also once opened, and the dump shows the same 

 kind of rocks as at the Portsmouth mine. 



A quarter of a mile south of the Bristol Ferry hotel the roadside shows 

 coaly shale, striking apparently N. 35° E., dip 50° E.; not satisfactory. 



A little south of the last exposure a road turns off eastward, toward 

 the south end of Town Pond. Here carbonaceous sandstone, some of the 

 layers coarse, contains fragments of carbonaceous shale, much crumpled, 

 apparently by a force acting east-west. 



A boring in Portsmouth, Rhode Island, examined by Mr. Collier Cobb, 

 gave the following record as regards succession and thickness, but no 

 account is taken of possible reduplication by faulting or folding. In this 

 table argillaceous strata in superposition and variously denominated argil- 



MON XXXIII 21 



