748 N. H. DARTON 
sea-level in several areas. Wittich' has presented many interest- 
ing facts relating to this subject with illustrations of shell deposits 
and shore features up to altitudes of 1,052 meters in a divide near 
Mission San Borja; this was as high as he ascended in his explo- 
rations. : 
The emergence has occupied a somewhat long time and may 
still be in progress. The shore erosion has been effected at vari- 
ous stages, although some of it may have been developed during 
the preceding submergence. The latter was apparently relatively 
transient, and most of the present configuration of the land was 
developed prior to this event. 
tErnesto Wittich, ““La Emersion Moderna de la Costa Occidental de la Baja 
California,” Soc. Cien. Antonio Alzate (Mexico) Memoirs, Vol. XXXV, pp. 121-44. 
