﻿352 W. M. Davis — Triassic formation, etc. 



to the left of that of the ridges. Farther north in Granby, the 

 range turns to the northeast, and here a north and south strike 

 of the schists would produce a receding overlap. Having de- 

 termined this from the conditions of the hypothesis, the mazes 

 of Percival's text were searched through with care, and it was 

 then found that the schists in Canton, close to the first-named 

 ridges, dip to the east-northeast, and therefore strike to the 

 north-north west (Geol. Conn., p. 78) ; while in the second local- 

 ity, the schists strike about north and south (Id., pp. 75, 293, 

 294). Further tests of this nature will be made by additional 

 observation in the field. 



There is a difficulty in the operation of the mechanical dis- 

 turbance that should be referred to. The faults are sometimes 

 so close together, that it is not easy to imagine them extending 

 downward across the whole series of underlying beds without 

 causing irregularities of dip ; and yet no such irregularity is 

 thus far discovered. But it may perhaps be that the present 

 surface of the ground was so deeply buried during the initial 

 stages of the disturbance, that the weight of the superincum- 

 bent mass, or gravitative form -destroying force, was then and 

 there greatly in excess of the strength of the rocks, or cohe- 

 sive, form-preserving force ; in such case, the fractures would 

 follow closely along the planes of greatest stress as indicated 

 by the slabs of schists, and once formed they would long re- 

 main the surfaces of easiest displacement. However this may 

 be, the hypothesis seems to accord well in its essential features 

 with all observations yet collected, and to possess something of 

 the prophetic power that may in time entitle it to be called a 

 theory. It may perhaps find application in other regions 

 where unconformable masses have been deformed together, 

 and the lesser, superficial mass has to accommodate itself to the 

 forms presented to it by the greater mass beneath. When com- 

 pression overtakes the region of northern France, where the 

 massive and steeply inclined coal-measures are covered uncon- 

 formably by a relatively thin sheet of Cretaceous strata, the 

 latter may be broken up into a number of tilted blocks, not 

 unlike our Triassic. It may be that even so great a faulted 

 monoclinal as that of eastern Tennessee owes a good part of its 

 structure to the reaction from its crystalline foundation. 



