EASTEEN SHOEE OF THE BAY. 271 



TI^nSKTON^. 



The granite escarpment trends N. 30° E. as far as the western side of 

 Pocasset Hill, changing thence to N. 13° E. as far as the exposures north- 

 east of the railroad bridge. The lowest exposures of the Carboniferous 

 series occur in the quarry on the hillside. Here the prevailing rock is 

 arkose. The lowest part of this arkose, stratigraphically, occurs very near 

 the granite. Nearer the lower end of the quarry blackish shale occurs. 

 Tracing the exposures northward, a whitish, fine-grained, quartzitic rock, 

 very much like the rock exposed west of East Greenwich, occurs between 

 the Carboniferous rock and the granite, and is evidently pre-Carboniferous. 

 Along the railroad tracks, overlying the grits, occur abundant exposures of 

 conglomerate, composed chiefly of quartzose pebbles, some of them 8 

 inches long. No granite pebbles were seen. Coarse sandstones are inter- 

 bedded. The abundance of quartzose pebbles and the absence of granite 

 pebbles here is paralleled at Steep Brook. The more northern exposures 

 along the railroad have a strike N.-S. and dip 30° W. At the quarry the 

 strike becomes N. 35° E., the dip 40° W. 



The next exposure of Carboniferous rocks occurs a mile and three- 

 quarters farther south, east of the northern end of Nannaquacket Pond. 

 At the northern end of the pond the granite appears at the shore. But a 

 short distance farther south, on the hillside, the arkose is seen resting upon 

 the granite. A little coaly shale is interbedded with the arkose. Strike 

 N. 20° W., dip 45° W. Farther south the granite comes down to the road- 

 side. It is evident that the contact line between the Carboniferous rocks 

 and the granite must turn westward where Sin and Flesh Brook enters the 

 pond. Granite occurs also along the northern side of Sin and Flesh Brook 

 near the pond, and also directly north of the pond, on the north side of the 

 road skirting the same. This would require a still farther westward trend 

 of the shore line. 



Returning to the arkose exposure, the granite comes down to the road 

 near the foi-k of the way. North of the road, after passing the turn toward 

 the east, the arkose occurs again high up on the hillside, but associated with 

 considerable coaly shale. The strike here is N. 85° W., dip 65° to 70° S. 

 If the observer crosses the road at its bend, he will find an excellent exposure 

 in the open area on the hillside, southwest of the wooded summit. Here the 



