404 University of California. tvol. 2. 



dip at low angles into the hill or northeasterly, while on the south 

 side, on the flanks of Fog Bluff, the same flows dip southwesterly. 

 This fact, taken with the very apparent dislocation of the strata on 

 the line of Wolsey Canon, establishes clearly the fact of a fault 

 along that line. 



Above these andesites is a formation of conglomerates and red 

 clays having a thickness of about 200 feet in the Pie Knob section, 

 but thinning out rapidly towards Fog Bluff and towards the north- 

 west. They have the same dip and were affected by the same 

 faulting as the andesites below them. The presence of these beds 

 clearly indicates the resumption of the lacustrine conditions for a 

 considerable time after the outflow of the lower andesites. The 

 formation is best seen in the sections on the north side of Wolsey 

 Canon, in the ravine to the east of Pie Knob, and in the quarry at 

 the north end of Pie Knob. On the southwest side of Fog Bluff, 

 where the rocks dip down the slope, their presence is indicated by 

 a heavily-soiled shelf and by the presence of pebbles in the soil. 



Above this formation is another sheet of andesite lava about 

 seventy feet thick. This forms the summit or cap of Fog Bluff 

 except for a few small residuary patches of fresh-water limestone 

 which rest upon and adhere to the upper surface of the lava. This 

 lava sheet is rather decomposed, and is in places oxidized and 

 ocherous. It, also, has been dislocated by the Wolsey Canon fault, 

 and beyond the fault to the northwest is traceable to the quarry at 

 the north end of Pie Knob and beyond. Still another small lens 

 of andesite lava lies above this to the east of Pie Knob. 



Even these lavas did not displace the Campan Lake, for we find 

 above them still later beds of conglomerate and clay which appear 

 to be traceably continuous with the main body of the lower 

 Campan formation, indicating that these various volcanic effusions 

 effected merely a local interruption in the deposition, and that the 

 process of sedimentation in the basin was continuous. 



Above these conglomerates and clays is another thin sheet of 

 lava which in the line of outcrop is discontinuous and which lias 

 the character of a transition from basalt to andesite and is classed 

 on the map as an andesitic basalt. 



Period of Faulting. —Up to this stage all the strata, whether 



