Cairnes — Some Suggested New Physiographic Terms. 87 



materials. In other districts, ashes and breccia, at times 

 accompanied by lava, have been added to surfaces in sufficient 

 amounts to fill many of the valleys and depressions, and thus 

 greatly reduce the topographic relief. 



Conclusion. 



In the foregoing paragraphs the writer has suggested certain 

 new physiographic terms and has defined their intended sig- 

 nificance. No attempt has been made, however, in this short 

 paper, either to write detailed descriptions of the equiplanating, 

 deplanating, and applanating processes, or to outline the geo- 

 graphical extent of their present and past activities. Volumes 

 might be written without exhausting these subjects which 

 include a great portion of the entire science of physiography, 

 so that only what are thought to be some of the fundamental 

 points and several principles concerning these processes are 

 here briefly considered. Even to enumerate and summarily 

 describe all the forces and agencies that contribute to equipla- 

 nation, deplanation, and applanation, and to delineate even all 

 the most important areas in, the world, where they are, or have 

 been, in operation, would cause this paper to assume propor- 

 tions far beyond what is necessary. 



Moreover, it has not been the writer's purpose to attempt an 

 interpretation of the various land-forms which might be con- 

 sidered ; and further, there is frequently a considerable diver- 

 sity of opinion among physiographers as to the origin of the 

 various features of many well-known regions, so that in case 

 any of these areas happened to be cited as illustrating the 

 results of certain processes here described, a misunderstanding 

 might arise as to the intended significance of the new terms 

 here suggested. 



It has thus seemed best merely to introduce the new terms 

 in relation to physiographic processes, and to offer a few sug- 

 gestions as to their usefulness and adaptability, and leave to 

 others their further application and development. 



