CHAPTER II. 

 THE WESTERN ISLANDS OF THE BAY. 



DUTCH ISLAND. 



From the western side of the island, nearer its northern end, a triangu- 

 lar piece of sandy beach extends into the western passage of the bay. 

 Southward from this beach there is a continuous exposure of Carboniferous 

 rocks along the shore. The more northern portion consists chiefly of black 

 shales, which sometimes are very coaly. At a point about 400 feet south 

 of the beach and directly west of the largest building on this shore, a 

 number of fern leaves were found in the coaly shale, the shale being free 

 from any marked signs of metamorphism, excepting the usual cleavage. 

 The strike of the shales is N. 30° E.; dip eastward, variable, but very dis- 

 tinct, averaging perhaps 45°. Sandy layers are more or less frequently 

 intercalated in the shales. Farther south there is an alternation of sand- 

 stone and conglomerates with some coaly shales. The strike is N. 30° E.; 

 the dip is still eastward. Along the last 1,000 feet sandstone prevails. 

 Here is shown a fine instance of crumpled strata. The layers can be well 

 distinguished, and the flexures which they have undergone can readily 

 be traced. Notwithstanding the flexuring, the dip of the sandstone can 

 be seen to be distinctly eastward. The strike is nearly north and south, or 

 slightly east of north. Near the light-house there is not sufficient exposure 

 to make a determination of the dip. Along the east shore northward 

 from the light-house the crumpling of the sandstone continues. A fine 

 exposure of conglomerate, forming a bed about 8 feet thick and free 

 from crumpling, shows the dip to be about 50° E. The strike is N. 20° E. 

 The conglomerate borders the western side of an embayment about a third 

 of the length of the island north of the light-house. The point forming 

 the eastern side of the embayment consists again of crumpled sandstone, 

 with a few thin layers of conglomerate, the dip being distinctly eastward 

 as far north as the wharf, a third of the length of the island from its northern 



