227 



are now regarded as bendiiiji' to the north with the sh()rc and 

 following the lower beds aronnd the bend. This great bend is, 

 of course, the extremity of the great central and dominant 

 anticline of Hingham, and that it is the extremity is proved l)y 

 the undeniable fact that the axis here plunges steeply down- 

 ward to the west. Southward from tliis axis the beds form a 

 monocline of from 80° to 85°, extending to Beal's Cove ; and on 

 the northwest side a monocline of from 85° to 90° extends out 

 beneath the level sandplain. 



At the time of my first observations in this locality, fifteen 

 years ago, I was deeply impressed by the fact, that there are, 

 northwest of the granite, two similar and parallel ridges of 

 conglomerate and melaphyr, with an intervening valley com- 

 posed chiefly of sandstone and slate. This strong topogrnphic 

 suggestion of a synclinc biased all my later ol)servations, until 

 the present writing compelled a broader and more rigid examinn- 

 tion of the fiicts, and the absence of any real geological evidence 

 of a synclinal structnre became apparent. 



Whichever view of the strncture of the beds on tlie north- 

 west side of the axis is accepted, important strike-faults must 

 be introduced to explain the second belt of melaphyr. This 

 melaphyr is essentially similar to that on the east side, against 

 the granite, and one naturally regards it at first as marking a 

 denuded anticline. Its eastern edge, however, is quite clearly 

 transjrressive with reference to the borderin<if strata ; and it 

 is necessary either to introduce a fault here or to regard the 

 melaphyr as a dike. No reliable dips have been observed in the 

 conglomerate on the west side of this melaphyr ; but it may l)e 

 reasonably correlated with that on the shore of Unit's Cove, 

 which dips westward away from the melaphyr and beneath the 

 slate series. This belt of melaphyr is a direct prolongation of 

 the great body of mela])hyr lying east of Unit's Cove, and can 

 not be regarded as intrusive unless we are prepared to ascribe 

 that origin to the entire area, or in fact to all the melaphyr of 

 Hingham. The fault separating the melaphyr from the slate 



