The Geotectonic Factor 



331 



//VD//J/V OCEAN 



Fig. 144. The drowned rivers of Sundaland, southeastern Asia. These indi- 

 cate that this entire area was above water when the Pleistocene ocean was at 

 its lowest level. (From Umbgrove, The Pulse of the Earth, courtesv of Martinns 

 Nijhoff. ) 



■'"■'^m^i^ry^ 



Fig. 145. The beheaded valley of Lundy Creek, near Mono Lake, California. 

 The rift was caused by the earthquake of 1872. (From Cloos, Conversation 

 with the Earth, courtesy of R. Piper & Co.) 



