462 University of California Publications. [Geology 



of Bear Mountain and finding the notch formed by the sub- 

 sidiary fault, which notch was originally lower, as it now is, 

 than the analogous notch made by the main southwest fault of 

 Bear Mountain. Prior to the capture of the valley by Sycamore 

 Creek it must have been occupied by a lake, since it is entirely 

 rock rimmed, but the hydrographic basin which includes the 

 valley is so small relatively to the area of the valley, that it is 

 quite improbable that the lake had an outlet by rising to the 

 level of the notch which was afterward deepened by the head- 

 water erosion of Sycamore Creek. 



University of California, 

 March, 1906. 



