222 



fine, gray, sometimes banded with brown, and thin-bedded, 

 with a few small contortions ; dip, average vertical. Beyond 

 this there is a gradual passage back to conglomerate, which 

 continues with a nearly vertical southerly dip for perhaps two 

 hundred feet, and then disappears beneath the drift. The gen- 

 eral line of strike is N. 60° E. Slaty beds in the conglomerate 

 show distinct cleavage oblique to the bedding, and dipping north 

 at the usual angle. The slate in this section is not shown on the 

 map. 



One-half mile further east, near the shore, there are many 

 large, loose masses of conglomerate with grits and sandstone ; 

 and one block, which appeared to be in situ, shows a high 

 southerly dip. 



On the outer end of Squantum the rocks of this belt are 

 well exposed, and the section is both complicated and interest- 

 ing. The synclinal is not clearly shown, but the faults are 

 sufficiently obvious. Beginning at the north shore, the first rock 

 is a slaty and sandy conglomerate, with many soft pebbles and 

 an imperfect sort of slaty cleavage, which shows the high northerly 

 dip characteristic of that structure in this region. The dip of 

 the conglomerate is S. 20° E. 50°-60°. This rock continues 

 for perhaps eighty feet, and is then overlaid conformably by 

 about three hundred feet, traverse measure, of a purplish-brown 

 slate, of a somewhat arenaceous texture, and occasionally banded 

 with greenish- white. This slate possesses true cleavage, and 

 has a southerly dip of 45°— 60°. It is succeeded by conglom- 

 erate, but the contact here is obscure, and I could not deter- 

 mine its nature satisfactorily. There seems to be no reason 

 to doubt, however, that the slate is either thrown down by a 

 fault, or that it lies in an inclined syncline, the latter theory being, 

 perhaps, the more probable. This second band of conglom- 

 erate has a breadth of five hundred or six hundred feet, dipping 

 S. 20° E. 30°-50°. At first there is considerable sandstone 

 interstratified, but higher the conglomerate is very coarse and 

 irregular, holding masses of granite, amygdaloid, etc., one to 

 three feet in diameter. Farther on it becomes finer again, and 



