BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 29, pp. 575-586 SEPTEMBER 30, 1918 



AGES OF PENEPLAINS OF THE APPALACHIAN PROVINCE ' 



BY EUGENE WESLEY STTAW 



{Presented before lite Socieit/ Decernher 21 , IdlO) 



CONTENTS 



Page 



Problem 575 



Methods of determining date of completion of a peneplain 575 



Times of formation of Appalachian peneplains 576 



Evidence as to age of peneplains 581 



General statement 581 



Correlation with buried peneplains 581 



Extent of Atlantic Coastal Plain deposits 583 



Nature of derived deposits 585 



Amount and rate of erosion 585 



Summary 586 



Problem 



The wide acceptance and nse of inferences concerning the presence and 

 approximate age of the peneplains^ covering in the aggregate almost all of 

 the Appalachian Highlands, make the dating of these peneplains a matter 

 of great interest and importance in deciphering the history of the region 

 and in interpreting the sedimentary deposits derived therefrom. Great 

 precision may perhaps never be possible; but on account of the importance 

 of the problem, it seems desirable to examine the data which have been 

 set forth and to add to them if possible. In this paper it is proposed to 

 accept Appalachian peneplains as tliey are described and to consider them 

 in the light of certain general principles and of published and unpublished 

 data concerning buried peneplains in the Atlantic and Gulf coastal plains. 

 No inferences except those relating to age are discussed, and the proposed 

 modifications are to be regarded only as suggestions. 



Methods of determining Datic of Completion of a Penei'l.vin 



Apparently the principal lines of attack for determining tlie time of 

 formation of a peneplain are as follows: The first involves correlating 



^Manuscript roceived by the Secretary of the Society September 11, 1017. 

 Published by permission of the Director of tlie U. S. Geological Survey. 



XLIII — Bull. Gkol. Soc. Aaf., Vol. 20, 1017 (575) 



