196 



characterized by the simplicity which this theory requires, it is 

 now vastly more complex. Instead of one great downfold of 

 the strata, there is a series of synclinals and anticlinals ; and, 

 as already stated, the most of the conglomerate has reached the 

 light through the eroded crests of the latter. 



"Whether or not the period of disturbance here implied fol- 

 lowed close upon the deposition of the slates, the absence of 

 more recent beds makes it impossible certainly to determine. 

 The amount of disturbance is clearly greater than among the 

 Carboniferous beds of the Narragansett basin, and probably 

 exceeds that of the rocks underlying these, and marked as 

 Devonian on the map. It is likely that all the deposits of the 

 Acadian epoch in this north-eastern border region were up- 

 turned simultaneously ; and hence, since it is known that, in 

 Newfoundland, the Potsdam beds lie unconformably upon the 

 Acadian, I conclude that although the disturbance of the Bos- 

 ton series, like the preceding subsidence, may have been gradual, 

 and of even greater duration, yet it had its beginning, at least, 

 before the close of Primordial time. 



The disturbance of this formation is manifested in three 

 distinct ways ; by folds, by faults, and by exotic masses. I 

 have named these stratigraphic features in the probable order 

 of their relative importance ; and yet I am not fully satisfied 

 as to whether plication or fracture is the more characteristic. 

 The plicating force appears to have operated with nearly 

 equal intensity from the north and south, or, rather, from 

 the north-north-west and south-south-east ; producing folds 

 with approximately east-west trends, though showing a ten- 

 dency at most points to parallelism with the adjacent crystal- 

 line border. As the detailed descriptions and sections will 

 show, these flexures of the strata vary greatly in form and 

 size ; including some that are exceedingly narrow, closely 

 folded, and even inverted, and others that are very broad and 

 gently arched. In the first kind the strata are much broken 

 by reason of having been so sharply bent ; and in the second 

 class the same result appears to have been reached through the 



