318 G. H. WILLIAMS — STRUCTURE OF THE PIEDMONT PLATEAU. 



dies out toward the north ; and between these is a plain, to which I think 

 the name Piedmont should be restricted. East of the coastward range lies 

 an undulating plain, for which I suggest the name Mldlamd plain; and east 

 of the Midland plain lies the Marine plain, sloping down to tide-water. 



Referring to the suggestion of enormous denudation, I consider the Appa- 

 lachians the western abutment of a range from which 15,000 feet of strata 

 have been eroded. 



Mr. Charles S. Prosser: Dr. Williams mentioned the occurrence of 

 fossils in the Triassic (Newark) of Maryland. This is a very interesting as 

 well important paleontological discovery. So far as I know, the only dis- 

 covery of Triassic fossil plants in Maryland hitherto annouuced is by Pro- 

 fessor J. P. Lesley, in a report on the geology of Chester county, Pennsyl- 

 vania, where a " plant bed in Frederick county, Maryland," is mentioned.* 

 Will Dr. Williams kindly give us the localities in which these fossils were 

 found, and also tell us something about their systematic position ? Are they 

 fossil vertebrates, invertebrates, or plant remains? 



Dr. Williams : Fossils have recently been found in two localities in the 

 Triassic of Frederick county, Maryland : first, by Professor Philip R. Uhler, 

 about two miles west of Frederick ; and, secondly, by Mr. S. L. Powell, 

 not far from Utica Mills. Those collected by Mr. Powell are from the red 

 shales, and are very abundant. Some of the forms resemble nuts ; others 

 may be interlacing roots. 



I have often considered the points mentioned by Professor Davis. The 

 fan structure is a false resemblance. The evidence that this structure is 

 rather apparent than real is: (1) The divergence of the synclinal axis from 

 the contact ; (2) The occurrence of the crystalline rocks on one side only 

 (east) of the axis. 



= Second Geol. Surv. Pa.. C 4, 1883, p. 29. 



