THREE NEW PHYSIOGRAPHIC TERMS 



709 



Lake Bonneville furnish others. (See Plates I, IX, XXI, XXII, 

 XXVI, and XXVII, Monograph I, U. S. Geological Survey.) 



In general, it may be said that any cause which brings about the 

 relations indicated above — namely, greater topographic age on the 



Fig. 2. — Topographic unconformity shown in contours, Oceanside, Cal., quad- 

 rangle. Scale, about one and one-fourth miles to the inch. 



upper part of a slope, and lesser topographic age on the lower part 

 of the same slope, with a distinct line or belt of separation between 

 the two — develops topographic imconformity. If the relations were 

 reversed, so that lesser age on the upper part of a slope was succeeded 

 by greater age below, the two phases of topography being sepa- 

 rated by a distinct line or zone, the result would also be a topographic 



