Page:Popular Science Monthly Volume 40.djvu/243

Rh 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 account 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 disturbance 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 upper surface should be inclined to the east; but this fails to represent the dislocations by which the mass is known to be traversed. The model was therefore made in several parts, each of which could be tilted independently of its neighbors, as shown in Fig. 10, the observer looking southeast. It is here made clear that while the dip of the beds is to the eastward, 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 surface, with steps from one part to another. If we may judge by the angle at which the beds lie, the elevated edges of these dislocated 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 tilting 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