TllKOKlKS OK IHE CAUSES OF FAllLTlNC; 199 



trend, and as far as I am aware, they offer the one 

 possible explanation. 



The combined phenomena of flexured trends and 

 transverse structure are associated with the drifting 

 conditions previously described, and constitute a great 

 buckle in the normal, north-southerly directions of the 

 continental trends whereby the regions to the north 

 and south of the Great Transverse Belt have moved 

 west and east to one another respectively. 



Studies of the structure pattern have convinced me 

 that the bending of the great belts of parallel struc- 

 tures of the Ventura Ranges which at one time may 

 have had rectilinear directions, has been accomplished 

 by great, horizontal, northwesterly-southeasterly pulls 

 in the earth's crusts, and not by northerly stresses as 

 asserted by Willis. Such movements may have re- 

 sulted in the relative driftings to the northwest and 

 southeast respectively of the regions to the north and 

 south of the San Andreas Rift. 



Such movements have produced the abnormal, north 

 65" west directions of the Valyermo section of the 

 San Andreas-Puente Belt and the faulting and the 

 flexuring of the Ventura Ranges. In some instances, 

 as in parts of Ventura County, the strains resulting 

 from the stresses of such bends have become breaks 

 with the resulting confusion and displacements of the 

 structure and the lineaments of the physiography. In 

 fact the torsional horizontal stresses and strain were 

 so great at one place that the curvature of the flexured 

 ranges collapsed into buckling as seen in both the in- 

 stance of the San Cayetano overthrust and in the dis- 

 turbed structural conditions adjacent to Hopper and 



