88 PROCEEDINGS OF THE AMHERST MEETING 



Discussion 



Professor Miller : From my own observations in the vicinity of North- 

 ampton, Massachusetts, I am certain that there has been downfaulting of 

 thousands of feet on the west side of the valley as well as on the east, as 

 shown by the fault-scarp and great crush zone in the city quarry of North- 

 ampton ; also, there is evidence for very considerable former extension of the 

 Triassic, both east and west of the present valley sides. For these reasons I 

 believe that the principles involved in all of the first three of Professor Foye's 

 sections should be combined by considering very appreciable downwarping at 

 first, and then trough faulting (possibly caused by loading of sediment), with 

 generally the most profound downward movement on the east, thus accounting 

 for the usual eastward dips. 



Professor Woodworth remarked that, in contrasting sediments on the east- 

 ern and the western sides of the Connecticut Valley in Connecticut, compari- 

 sons relate generally to the top and bottom of the Triassic respectively. 



Professor Davis said that he felt much satisfaction at the progress of Pro- 

 fessor Foye's work on the Connecticut Triassic and expressed the hope that 

 it might be continued, especially in the direction of searching for new locali- 

 ties of upper contacts between the lava sheets and overlying sediments ; for 

 new outcrops of fossiliferous black shales both anterior and posterior to the 

 main trap sheet and at new horizons; for new examples of shales slicken- 

 sided on bedding planes, as if the result of a sliding accommodation to the 

 warping of faulted blocks ; for additional evidence by which the trace of 

 faults can be followed in the Triassic area ; and, most important of all, for 

 new evidence of the continuation of the Triassic faults into the eastern and 

 western highlands of crystalline rocks. As to the modifications suggested by 

 Professor Foye in the speaker's hypothetical cross-sections, published over 

 twenty years ago in his report to the U. S. Geological Survey, a diagram is 

 always a venturesome means of representing a hypothetical condition, because 

 it is necessarily definite, while the hypothetical condition is preferably vague 

 and shadowy. The proposed modifications in the diagram are therefore inter- 

 esting and welcome. A fault along the western margin of the Triassic might 

 probably be introduced to advantage in certain districts, but whether such a 

 fault was produced during tbe deposition of the Trias or afterwards, or both, 

 is not easily determined. The speaker closed by saying that in any case it 

 was a satisfaction to see that he had suffered more from his diagram than 

 from his ideas. 



Professor Gordon : In favor of pre-Triassic faulting in the formation of the 

 Newark basin, I have been impressed with the coarseness of the material 

 along the eastern border, at least in Massachusetts, which it has seemed to 

 me offers suggestion of steep slopes which might well have been favored by 

 fault displacements. It is plain that in any attempt to account for the con- 

 figuration of the Newark basin by faulting care must be exercised not to con- 

 fuse displacements of very different age and therefore of very different sig- 

 nificance. 



Professor Long well : Extreme coarseness and angularity of material are 

 prominent characteristics of the Triassic near the eastern fault boundary in 

 southern Connecticut. The "boulder ridges'" north of P>ranford, accurately 

 described years ago by Dana and Hovey, are made up of tbe most typical 



