PROC. CAL. ACAD. SCI., 4th Series, Vol. XI 



[DICKERSON] Plate 37 



Fig. 1. Sonoma Mountain, Hayward Fault, 

 mile southeast of the Petaluma Reservoir. 



Looking northwest from a point one 



Fig. 2. A surface in late maturity. Sonoma Mountain one-eighth of a mile southeast 

 of Petaluma Reservoir. The Hayward rift beheaded the stream once draining across the 

 surface and its drainage is now southwest by way of Rodger's Creek. 



