696 WILBUR G. FOYE 



the dips of the beds at the same horizon on the two sides of the 

 trough, but only basal beds are exposed on the western side of the 

 valley and upper beds on the eastern side. It is, however, possible 

 to compare the known dips of the upper beds to the east with the 

 dips of the basal beds to the west. Allowing for an erosion of 500 

 feet, the beds at the eastern side of the valley cannot He far below 

 the top of the series. Their original attitude at the close of the 

 Triassic sedimentation was approximately horizontal. In the case 

 of the geosynclinal hypothesis there may have been a slight dip 

 to the west; in the case of the fault-monoclinal hypothesis, possibly 

 a slight dip to the east. At present they have an average dip of 

 15° to 20° to the east. It is difficult to beUeve that the post- 

 Triassic tilting was very dissimilar on the two sides of the valley. 

 If it is assumed that the present dip of the upper beds was developed 

 entirely at the time of the post-Triassic faulting, and that the tilt 

 was, therefore, approximately 20° to the east, then, by adding 20° 

 to the angle a, the present angle of dip of the basal beds at the 

 western side of the valley should be obtained. Davis (see above) 

 states that the average dip of the basal beds on the western side of 

 the vaUey is 20° to 30°.- In Case I (Fig. 6) by the foregoing method, 

 the dips should be from 30° to 40°. In Case II (Fig. 7), angles from 

 20° to 30° are to be expected. It is true that, if the Pomperaug 

 Valley area is included within the main basin, the results are incon- 

 clusive, but few authorities believe the original basin was much 

 larger than it is today. 



Assuming that the present dip of the upper beds of the Newark 

 series at the eastern side of the valley represents the approximate 

 angle of tilt to the east developed at the time of the post-Triassic 

 faulting, then referring to Davis' diagram (Fig. 5), and conceiving 

 that the present width of the valley was its approximate width in 

 the Triassic period, in Case I the present dips should vary only 

 slightly from the east toward the center of the valley, averaging 

 perhaps a little lower about midway between the two points, but 

 they should rise to a maximum at the western border. No normal 

 dips near the center should be greater than the dips at the eastern 

 border. In Case II there should be a progressive increase in dip 



