202 SOUTHERN CALIFORNIA C}p:OL()GY 



guez and Piiente Ranges shows a fold with secondary 

 faulting on its north side adjacent to the Puente Range. 



CAUSES OF THE CHANGES OF TRENDS 

 These deflections of the various trends from a nor- 

 mal, north-south direction may reflect stages in the 

 continental history when the trends swung partially 

 around the circle of directions, first from north-south 

 to northwest-southeast ; then from northwest-south- 

 east to northeast-southwest ; from thence to east- 

 west ; and from thence back through the arc to north- 

 west-southeast again. All of which conjectures are 

 theoretical. 



The theory that the various directional belts may be 

 of different ages, is a striking one for which we, at 

 present, see no explanation, except that they may 

 reflect changes in the position of the earth relative 

 to the direction of the polar axis. While that vague 

 form of history known as "myth," which came down 

 by word of mouth to the ancient Egyptians, Jews, 

 Hindus and Chinese, supports it, geologists are divided 

 as to whether such changes have ever taken place and 

 some astronomers repudiate the idea entirely. Weg- 

 ener, however, approves the theory ^ 



If such changes have taken place, it would not be 

 diffcult to conceive that they had resulted from the 

 isostatic efi'ects of adding to or subtracting from local 

 crustal loads portions of the crust by the accumulation 

 or melting of the gigantic ice sheets during the glacial 

 stages of the Pleistocene epoch. 



'Orifiin of Continents and Oceans p. 128. 



