FOREWORD 



This report will embrace brief statements of the 

 general earthquake conditions in Southern California, 

 with reasons for believing that alarming predictions of 

 a future earthquake of great severity are unfounded. 

 Also it will contain a conspectus of some of the hitherto 

 unpublished fundamentals of the geology and physi- 

 ography of Southern California which give individ- 

 uality to this interesting country and without which no 

 intelligent concept of the seismologic conditions can 

 be formed. 



One step in the undertaking will be to define and 

 describe Southern California, and to show that it is a 

 different and distinct region from the northern part of 

 the State. It is the failure to understand this dif- 

 ference that has in the past caused much misunder- 

 standing. 



An attempt will also be made to point out the essen- 

 tial features of the complicated structure of the region, 

 presenting many new characteristics not found in the 

 earthquake map.^ Space and time will not allow much 



'Fault Map of California. Compiled fi-om Data Assembled by the Seismo- 

 logical Society of America. Compiled by Bailey Willis and H. O. Wood. 

 1922. (Place of publication not given). Inasmuch as I was invited to con- 

 tribute to this map by Dr. Wood, and prevented from so doing by illness. I 

 feel a delicacy in criticizing it. But I cannot refrain from expressing my 

 disappointment at the facts that the relief which was originally depicted with 

 great delicacy and beauty by Mr. Renshawe, was so ineffectively reproduced : 

 that the map makes no distinction between the master and interior faults or 

 their degrees of prominence, and that their conspicuous relationship to the 

 physiography is not shown. 



