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tlie conglomerate. Tlic pebbles of limestone are of quite uni- 

 form character ; and are to be recognized especially l)y the 

 mode of weathering and the behavior with acid. The rock is 

 dull gray, finely and imperfectly crystalline, evidently impure, 

 and leaves a large insoluble residue when treated with acid. 

 Where the segregation of the calcareous debris has occurred in 

 the finer — sandy or slaty — portions of the ccmglomerate, the 

 resulting forms are sometimes difiicult to distinguish from the 

 original pebbles. The further consideration of the source of 

 tliese fragments and of the light which they throw upon the 

 age of the enclosing rocks may most profitably be reserved for 

 the general discussion of the age and relations of the Hinoham 



o o o 



strata. 



On following the conglomerate north it is found to end 

 abruptly, as shown on the map, against the slate. The 

 contact, which is clearly exposed and can be traced over the 

 clifF, is transverse to the strike of both rocks and a very obvious 

 fault. The fault-plane strikes N. 80° E. and hades to the north 

 10°, and parallel with it the slate shows a very marked cleavage. 

 On account of the cleavage, and the consequent shaly character 

 of the slate near the surface, the true bedding is difficult to 

 make out. It can be proved, however, that the dip has the 

 normal westerly direction fin* this shore, but is somewhat 

 steeper than usual. Along the fault-line, for a thickness of a 

 foot or so, the slate is distinctly comminuted, having, evidently, 

 experienced unusual compression and friction ; and in the con- 

 glomerate, parallel with the fault, may be observed several more 

 or less distinct planes of either cleavage or shearing. The 

 marked cleavage of the slate is evidently a local feature, for 

 along the north side of the cove, 400 feet distant, it is scarcely 

 noticeable, being quite subordinate to the joint-structure. We 

 may, therefore, find a sufficient explanation of the cleavage in 

 the fact that the slate, as the result of the faulting, has been 

 dropped down along side of the massive conglomerate and then 

 squeezed up against it. 



