Shaler.] 112 [February 1, 



A revision of the evidence which led me to this opinion of the 

 origin of the great bays of the Chesapeake and the Delaware, and 

 secondly, of the source of the sands and muds which make the sand- 

 bars and mud- flats to the south of them, has confirmed me in the 

 opinion expressed a year ago. A glance at the map will show, how- 

 ever, that the fringing reefs of the Hatteras shore are only the ante- 

 cedents of this part of the coast ; remove them entirely and the diffi- 

 culty of explaining the prominence of Cape Hatteras remains. 

 Stripped of these reefs the shore would still present essentially the 

 form it does at present. 



A careful examination has satisfied me that the projection of 

 Hatteras is due to subterranean disturbances which have resulted in 

 uplifting the whole of this part of the coast. We shall have to go 

 to some distance from the cape itself in order to find the evidence of 

 this uplifting action. Upon a north and south line which passes 

 through Richmond, Virginia, there exists a hitherto little noticed 

 fold of the rocks having an altitude of over one thousand feet. On 

 examining this ridge carefully, we shall find that it is elongated 

 in the fashion of all great plications of rocks, and that it extends from 

 Richmond, where it seems to sink down to the northward, as far as 

 Weldon, N. C, having a length of at least fifty miles ; its east and 

 west development is much less, probably being not more than ten to 

 fifteen miles at the base. On comparing the general character of this 

 ridge with the separate ridges of the Alleghanies we find a very 

 close resemblance. We are drawn to the conclusion that the similar- 

 ity of form and the identity of direction indicate that this ridge is to 

 be regarded as an outlying member of the Alleghany chain. It may, 

 at first sight, seem an extravagance to term this ridge a mountain 

 chain, it giving no conspicuous evidence of its existence on 

 the surface. Although there is no external relief, the uplift of the 

 rocks beneath the surface is as great as in the case of those ridges 

 which still have a conspicuous relief. 



The true explanation of this peculiarity is that this ridge has been 

 to a great extent worn down, and covered by subsequent accumula- 

 tions of sedimentary materials. 



The geological structure of other points along this chain, to the 

 eastward of the elevated region, indicates the same extensive erosive 

 action as would have been required to reduce the Richmond elevation 

 to its present height. 



The upturned edges of the old series of rocks which crop out 



