Triassic Fault of Southern Connecticut. 495 



quite a coincidence if in the case of each one of the cross 

 faults the base of the Triassic were near enough to the 

 present surface of the upland to be brought down below 

 the level of the lowland by such small faults ; and, as the 

 South Manchester Block is over two miles wide, and the 

 South Glastonbury Block is 4 or 5 miles wide, it is still 

 more remarkable that the crystallines are not brought to 

 the surface by the normal 10 to 15° dip of the Triassic. 



If, as has been shown previously, the Triassic did not 

 extend east of the Great Fault, we must seek some other 

 method of explaining the offsets. Three hypotheses may 

 be considered: (1) The main fault may have been dis- 



Fig. 6. 



Fig. 6. — Diagram to illustrate Davis's theory of the cross faults. 



placed to the east on the north side of the offsets by great 

 horizontal movement; (2) The apparent displacement 

 may be caused by the westerly dip of the fault plane; 

 (3) The cross faults may have been lines of weakness 

 when the course of the great fault was determined, and 

 where it met one of these lines of weakness it may have 

 followed it for some distance before continuing its north- 

 ward course. 



The first theory need not be considered further, for 



