THE LOST VOLCANOES OF CONNECTICUT. 



231 



up so as to form n land area, it was at least a subaqueous plain of 

 very even and level surface. The deeper layers of the formation 

 may have sagged a little toward the middle of the estuary on ac- 

 count of the progressive depression that the region had suffered 

 during the accumulation of the entire mass, but their departure 

 from horizontality was moderate. Yet at present the whole series, 

 with but trifling exceptions, inclines at an angle of twelve, fifteen, 

 or twenty degrees to the eastward. Evidently a serious disturb- 

 ance has affected the original attitude of the beds. 



The eastward slant or dip of the series might be imitated by 

 tilting the model over 

 bodily, so that its up- 

 per surface should be 

 inclined to the east ; 

 but this fails to rep- 

 resent the dislocations 

 by which the mass is 

 known to be traversed. 

 The model was there- 

 fore made in several 

 parts, each of which 

 could be tilted inde- 

 pendently of its neigh- 

 bors, as shown in Fig. 

 10, the observer look- 

 ing southeast. It is 



here made clear that while the dip of the beds is to the east- 

 ward, the course of the fractures by which they are dislocated 

 is northeastward ; this relation prevailing in a very constant 

 manner in the region of the Meriden ash-bed. The blocks into 

 which the mass is thus divided, five of which are shown in the 

 model, have been moved by moderate amounts on one another ; 

 the movement varies from a few feet up to two thousand. This 

 is called faulting, and its effect in this case is manifestly to break 

 up the continuous surface of the inclined plane that would have 

 been formed by simple tilting, and produce a discontinuous sur- 

 face, with steps from one part to another. If we may judge by 

 the angle at which the beds lie, the elevated edges of these dislo- 

 cated blocks must have once risen high into the air, producing 

 mountainous ridges of no insignificant relief. Yet at present 

 nothing of this ancient constructional form is apparent. The tilt- 

 ing and faulting were both done so long ago that no part of the 

 original surface remains. It has all been worn away. The best 

 evidence of the antiquity of the dislocations is found in another 

 State. 



Down in New Jersey, the corresponding red sandstone forma- 



FiG. 10. 



