46 LEOPOLD REINECKE 



"Beveled hills" are old erosion surfaces with dominant dis- 

 cordance between topography and structure, with a general absence 

 of irregularities of slope, and with deep soil covering. In addition, 

 one may expect to find on them the accessory characters of partial 

 accordance between topography and structure and occasional cliffs 

 and flat areas. It is proposed that the term be confined to forms 

 with average regional slopes of from 3 to 6 per cent and that the 

 upland portion of the Interior Plateaus of British Columbia be 

 considered the type of this land form. 



The subdivision is desirable because it will stimulate the meas- 

 uring of regional slopes and thus assist in working out the physio- 

 graphic development of the surface and diastrophic movements of 

 the crust after its formation. It is not contrary to the accepted 

 hypotheses of the genesis of a land form through the normal cycle 

 of erosion, for the degree of slope is a factor in the manner, as well 

 as the rate of development, of an erosion surface. 



The objections to the subdivision are that it is arbitrary, that 

 a true average of the regional slopes on a land form are hard to get, 

 and that it involves more field and office work than are otherwise 

 necessary. The objections are met in the following manner. 



The type form "beveled hills" is represented by an old erosion 

 surface, which is found throughout the southern portion of a large 

 geographic unit, the Interior Plateaus of British Columbia. The 

 subdivision is therefore not entirely arbitrary. The difficulty of 

 obtaining a true average of the regional slopes on a land surface 

 can be met by taking account of the relative area occupied by slopes 

 departing from the general average. It is thought, finally, that 

 the extra field work involved in traverses over the region will be 

 of advantage in calling attention to details of physiographic interest 

 which can be obtained in no other way. 



It is well to repeat here that the object of this paper is first of 

 all to point out the importance of the study and determination of 

 regional slopes on old erosion surfaces, and that the particular form 

 of subdivision proposed is not considered final. 



