ORIGIN OF THE TRIASSIC TROUGH OF CONNECTICUT 691 



of once much more extensive deposits .... preserved by being 

 faulted beneath the level of erosion.'" 



Again, Professor Davis suggests that the trough may have been 

 developed by faulting movements on each side of the depression 

 (Fig. 2), whereas Professor Barrell^ has limited the faulting to the 

 eastern border (Fig. 3). 



It is believed that there is general agreement with Professor Davis' 

 statement that the ''ancient mountains of Western Upland must 



Fig. I. — Diagram representing a depression formed by a gradual bending down- 

 ward of a canoe-shaped trough, without faulting. 



Fig. 2. — Diagram representing a depression developed by faulting which was 

 continuous during the period of sedimentation. 



have been worn down to a peneplain, or at least reduced to hills 

 of moderate elevation and gentle slope, at the time the accumu- 

 lation of the sandstones began.'*^ It is further agreed that "the 

 basement on which the Triassic strata rest" was worn "so low that 

 no great additional amount of waste could be worn from it" had 

 there not been depression of a central area accompanied by "corre- 

 lated elevation of the adjoining areas on the west and east."^ 



Professor Davis goes on to say that "two suppositions may be 

 made as to the character of these correlated elevations. The 



^ A. W. Grabau, Text Book of Geology, Vol. II, pp. 612-13. 



^Joseph BarreU, "Central Connecticut in the Geologic Past," Bulletin No. 23, 

 Conn. State Geol. and Nat. Hist. Survey. 



3 Eighteenth Annual Report, U.S. Geol. Surv., Vol. II, p. 25. 

 '* Ibid., pp. 37-sS. 



