BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 8, PP. 221-226, PL. 20 MARCH 6, 1897 



EROSION AT BASELEVEL* 



BY MARIUS R. CAMPBELL 



(Read before the Society December 29, 1896) 

 CONTENTS 



Page 



Present conception of the ultimate result of undisturbed erosion 221 



Local baselevels in the Appalachians 222 



General characteristics in the areas observed 222 



Peculiar characters not explained by present theories 223 



Evidence of solution at baselevel afforded by etched pebbles and geodes 224 



Conclusions respecting the extent and character of erosion at baselevel 225 



Present Conception of the ultimate Result of undisturbed Erosion. 



The cycle of erosion as outlined by Davis is now generally accepted 

 as the normal succession of events in an undisturbed area, and its final 

 result, the baseleveled plain, is likewise regarded as the great datum 

 plain in all physiographic investigation. 



Since this physical feature has attained such prominence in the study 

 of modern geography, it seems opportune to inquire, What is the ulti- 

 mate result of undisturbed erosion ? Is it possible under such circum- 

 stances to produce a perfect plain, or will there always be irregularities 

 of elevation and the surface remain merely a peneplain ? 



So far as the writer is aware, no one has attempted a complete analysis 

 of the processes of erosion during the final stages of the cycle. It has been 

 frequently said that the result is a baseleveled plain, but it is doubtful if 

 the words have ever been used with their strict significance. Davis, who 

 has so clearly described the processes of erosion in the preceding stages of 

 the cycle, makes only a general statement like the following : f 



"Any mass of land constituting a single geographic individual or a natural group 

 of such individuals must, as soon as it is exposed to the destructive forces of the 

 atmosphere, begin its long sequence of development, and if no change of level 

 happen to it, it must at length be worn down smooth and low to a featureless 

 plain." 



* Published with the permission of the Director of the U. S. Geological Survey. 

 f Methods and Models in Geographic Teaching ; Am. Nat., vol. xxiii, p. 569. 



XXXII— Bull. Geol. Soc. Am., Vol. 8, 1896 (221) 



