Association of American Geologists mid Naturalists. 171 



tide might have prevented any horizontal deposition far out from 

 the margin ; and thirdly, that a gentle and steady risi^ig of the 

 region would, in conjunction with the proximity of the channel, 

 tend to maintain both the slope of the sediment and the lateral 

 advance of the shore which the hypothesis requires. 



Mr. Benjamin iSilUman, Jr., referring to the formation of the 

 Connecticut valley only, considered a part of the present inclina- 

 tion of the beds to be the result of upheaval, connected with the 

 outbursting of the trap. 



Prof. W. B. Rogers made some remarks corroborating the 

 views of Prof. H. D. Rogers in their application to the middle 

 secondary or new red sandstone strata of Virginia and North Car- 

 olina. He described this group of rocks, consisting of shales, 

 slates, sandstones and conglomerates of various tints of red and 

 gray, as extending with some considerable interruptions in a nearly 

 S. S. W. direction, entirely across the State of Virginia, and for 

 some distance into North Carolina. With but a few local excep- 

 tions he had found the dip throughout this belt to be N. W. or 

 N. N. W. Though destitute of the wide and prolonged ridges 

 of trap met with in the corresponding districts of Pennsylvania 

 and New Jersey, this region includes a great number of small 

 dykes and knobs of trappean rock, penetrating the sedimentary 

 strata, but in no instance causing any well marked change of dip 

 in the adjacent beds. The materials of these strata Prof. R. 

 stated to be very clearly traceable to the region of gneissoid and 

 schistose rocks lying to the southeast of the tract, and in some 

 cases, as in the limestone pebbles included in the conglomerate, 

 could even be referred to the individual beds from which they 

 had been torn. 



He supported the opinion maintained for some years past by 

 Prof. H. D. Rogers, that the inclination of the strata is not due 

 to a tilting action subsequent to their deposition, but is the simple 

 consequence of the influx of detrital matter from the southeast, 

 and its deposition in a series of northwest-dipping planes. As 

 gready favoring this view he mentioned the fact generally ob- 

 served in this belt throughout Virginia, that the strata become 

 steeper in their inclination as we proceed towards the northwest ; 

 whereas the reverse should have been expected from a force tilt- 

 ing them from a horizontal or gently inclined position into the 

 present northwestern dips. This opinion he conceived, was still 



