Bocks in Southern Connecticut. 231 



agrees Well with the average for normal faults in general. 

 It is true that if we imagine the beds turned back to a 

 horizontal position (or perhaps a few degrees past the 

 horizontal, to allow for an original westward dip on a 

 bajada slope), most of the faults would then be inclined 

 steeply eastward; but this would represent the extreme 

 conception that faulting began precisely at the time of 

 initial tilting, and even with this allowance the planes 

 would be so nearly vertical that they could not be con- 

 sidered as the result of ordinary shearing stresses. 



The testimony furnished by this one group of struc- 

 tural features is of course only suggestive, and is pre- 

 sented here merely as a possible small part of the cumu- 

 lative evidence through which we may eventually deter- 

 mine, with a reasonable degree of assurance, the 

 mechanics of post-Triassic faulting in the Connecticut 

 Valley. 



II. Triassic Fax Deposits. 



The prevalence of coarse sediments along the eastern 

 border of the Triassic area has attracted the attention 

 of all geologists who have worked in the region. Coarse 

 conglomerate containing an abundance of fresh feldspar 

 is the type of rock found almost universally in outcrops 

 immediately west of the great bounding fault. Pebbles 

 and bowlders of crystalline rocks included in this con- 

 glomerate can be traced to their sources in the meta- 

 morphic and igneous formations of the Eastern Highland. 

 As a rule the bowlders are fairly well rounded and do not 

 exceed a few inches in diameter ; but at certain localities 

 adjacent to the fault the fragments in the conglomerate 

 are unusually large and many are remarkably angular. 

 Some of the fragments belong to exceptional and distinc- 

 tive rock types which can be seen in place only in bodies 

 of limited size exposed immediately east of the fault. 

 The distance to which these coarse deposits were orig- 

 inally distributed westward cannot be ascertained, 

 because the beds now dip steeply to the east and have 

 been bevelled by post-Triassic erosion. Along the strike 

 the coarse material at a typical locality has a center of 

 maximum thickness and coarseness, grading into finer 

 sediments in either direction. This peculiar distribution, 

 considered in connection with the rude and lenticular 



