64 PROCEEDINGS OF THE ASSOCIATION OF 



absence of a parallel order of succession in the members gf the 

 two formations, tends likcAvise to strengthen this opinion. 



]\Ii-. Lyell conceived the steepness of the dip, which sometimes 

 amounts to twenty degrees, but more especially its direction, — 

 transverse to the course of the ancient estuary, to present a diffi- 

 culty. Prof. R. endeavored however to show that the present dip 

 might have been the original one, by suggesting, first, that there 

 is evidence, in the nature of the materials of the great southern 

 basin, for believing that they entered the estuary laterally on the 

 outcrop side, by streams flowing from a country of decomposing, 

 talcose, chloritic and hornblende rocks ; secondly, that if the 

 channel was near the same shore, the velocity of the tide might 

 have prevented any horizontal deposition far out from the margin ; 

 and thirdly, that a gentle and steady rising' 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 Silliman, 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 

 Carolina. He described this gi'oup of rocks, consisting of shales, 

 slates, sandstones and conglomerates of various tints of red and 

 gi-ay, as extending with some considerable inteiTuptions 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 bolt 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 gi-eat number of small 

 dykes and knobs of trappean rocks, penetrating the sedimentary 

 strata, but in no instance causing any ^vell-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 schis- 

 tose rocks lying to the soutlieast 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, 



