236 C. R. Long iv ell — Triassic Rocks in Connecticut. 



any faulting immediately preceding the fan deposition 

 was not accompanied by perceptible tilting of the Triassic 

 floor in this area. It is also to be noted that in a complete 

 section across the Triassic at this latitude the dips are 

 much steeper on the east than on the west. In the vicinity 

 of West Rock the eastward inclination is 20° to 25° ; at 

 East Rock it is about 20 3 ; between Fair Haven and East 

 Haven it ranges from 20° to 30° ; and from East Haven 

 to the eastern boundary the average is about 35°. This 

 relationship is directly the opposite of that observed for 

 the Connecticut Valley as a whole. Davis 11 was the first 

 to point out a perceptible decrease in dip from west to 

 east, basing his statement on the observed inclination of 

 basal beds exposed on both sides of the valley. He inter- 

 preted this relationship as favoring the hypothesis of 

 downfolding of the Triassic trough during sedimentation. 

 Others consider the entire section exposed on the eastern 

 side of the area as younger than the basal beds on the 

 west, and have cited the decreasing dip from west to east 

 as favoring the hypothesis of repeated faulting along 

 the eastern side during sedimentation, with progressive 

 tilting of the Triassic floor. 12 Another possible inter- 

 pretation is suggested here. If the monoclinal tilting of 

 the Connecticut Triassic is due to uplift along a geanti- 

 clinal axis to the west— and this is a popular conception — 

 we should expect a gradual decrease in dip toward the 

 east, with increasing distance from the axis of uplift. It 

 is seen, therefore, that the relation between dips on the 

 two sides of the valley agrees with several different 

 hypotheses but actually proves none. However, as dis- 

 cussed above, there is other and more direct evidence of 

 recurrent faulting on the east. 



A ready explanation of the higher dips on the east in 

 southern Connecticut, in contrast with the general rela- 

 tionship, is found in the powerful warping reflected by 

 the curving of Saltonstall and Totoket ridges. This pro- 

 nounced folding, which has materially modified the mon- 

 oclinal^ structure, appears only in the southern part of the 

 Triassic area. 



11 Davis, W. M., op. eit., pp. 38-39. 



12 Foye, W. G., in a paper on Connecticut structure presented before the 

 Geological Society of America, 1921; Bice, W. N., in discussion of Foye's 

 paper. 



