CHAPTER V. 

 THE EASTERN SHORE OF THE BAY. 



STEEP BROOK. 



Pre-Carboniferous granite forms the steep slopes of the hilly country 

 bordering Taunton River on the east. The western line of outcrop of the 

 granite extends from Steep Brook northward as far as the point where the 

 My rick branch of the railroad leaves the main line. The line of outcrop 

 of the granite then turns abruptly eastward and follows the southern side of 

 the railroad as far as Washington Mountain. At Steep Brook the granite 

 is well exposed along the sides and in the bed of the brook. The contact 

 with the Carboniferous rocks is not exposed. The lowest exposure of clastic 

 rock consists of conglomerate, strike N. 45° E., dip 30° W. Toward the 

 north, overlying the conglomerate, is sandstone, with a dip of 40° W. 

 Thirty feet west of the conglomerate there was not long ago exposed a 

 narrow coal seam, with coaly slate containing fern impressions. Its strike 

 was N. 15° E., dip 20° W. West of the coaly layer occurs a considerable 

 thickness of arkose, in some places scarcely showing' bedding, in others 

 indicating the planes of bedding by color banding caused by more carbo- 

 naceous material in certain thin layers. A little of the arkose material 

 exists beneath the coaly layer. The arkose consists chiefly of quartz, 

 derived from decayed granite. The quartz grains as a rule are not rounded. 

 The granite which furnished the constituents of the arkose must have been 

 reduced to a mass of loose material by aerial decomposition, so that the 

 quartz grains were readily washed away in order to form the arkose, while 

 the feldspathic material formed interbedded layers of the impure kaolin, 

 which was once quarried by the owner of the premises for shipment to 

 pottery works. The absence of the arkose and clay material near the base 

 of the series here is noteworthy. Still more important is the conglomerate 

 layer near the base, for the conglomerate, although so near the granite 

 area, does not consist of granite pebbles, but of quartzitic pebbles, often 3 



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