194 GEOLOGY OF THE NARttAGANSETT BASIN. 



feet south of the northern border, is a probable outcrop of gray Carbonifer- 

 ous sandstone in the street; it may be a large bowlder. Bowlders of the 

 same lithological texture are abundant upon the surface. Southward to 

 the limits of the quadrangle no outcrops have been found. 



Eastward, in the vicinity of Hanover Four Corners and near the east- 

 ern igneous border, several outcrops of the carbonaceous series appear. 

 Beginning on the northeast, in South Scituate on the east bank of Third 

 Herring Brook there is either a large bowlder or an outcrop of sandstone 

 with bands of small pebbles. Southward, where the road from Hanover 

 Four Corners to North Pembroke crosses North River, there are good 

 exposures, forming a narrow defile through which the river escapes from a 

 broad valley on the west to the wide channel extending beyond this cut 

 to the sea. The strata are sandstone and arkose with coarse grits, bands 

 of slate, and carbonaceous matter, striking in an east-west direction and 

 standing at high angles. On the south side of the river, in August, 1889, 

 there was found in a coaly seam the stem of a calamite. 



One and a half miles farther up the North River, where it is crossed 

 by the west road from the Corners to Pembroke, other exposures of the 

 Carboniferous conglomerates and sandstones occur, on the south side of the 

 stream. At the edge of the stream, in July, 1889, conglomerates and 

 sandstones were exposed under a mill. The bedding was much obscured 

 by joints. A few rods southward a blue compact sandstone is exposed, by 

 the roadside, apparently overlying the above-named beds. Across the road 

 and a few yards south of this cut a well was sunk, in July, 1889, through 

 10 feet of till into a dike of fine-grained, dark-colored diabase containing 

 numerous inclusions of granitic quartz from one-eighth to one-half inch 

 across, and a few pieces of feldspar. Angular fragments of red granitite 

 also occur in the diabase. 



Half a mile farther up the river the stream lays bare a section of 

 closely jointed sandstones apparently dipping northward. In the bank 

 above the carriage road there is much carbonaceous waste. In the road 

 ascending the hill at the head of the westernmost of the three headwater 

 branches of Swamp Brook, in Pembroke, black clays occur, which are also 

 met with in excavations on the adjoining land. The relations of these 

 deposits are very uncertain. 



