Lawson ~l 

 PalacheJ 



The Berkeley Hills. 



405 



sedimentary or interleaved volcanic, have been dislocated by the 

 Wolsey Canon fault. But the rocks above this show no evidence 

 of faulting, and the trace of the fault plane appears to pass beneath 

 these higher formations at the head of Wolsey Canon. There is 

 evidence, moreover, that it appears from beneath the same forma- 

 tions again on the far side of Gopher Ridge, in the upper part of 

 Wildcat Canon, as the mapping indicates. But this is precisely 

 the same horizon at which the Canon fault described on a previous 

 page, passed beneath the higher formations of Gopher Ridge. It 

 would seem, therefore, that the Canon fault and the Wolsey Canon 

 fault occurred at the same time, and we are thus able to define 

 narrowly the exact stage in the accumulation of the Campan 

 series at which the Campan basin was converted into a dislocated, 

 diastrophic trough. 



These two faults intersect at a point about 1,250 feet north of 

 Little Grizzly Peak, beneath the mantling formations, and at this 

 point there is a curious sink-like depression in the hillside, as is 

 indicated by the contours of the map. The depression resembles 

 a landslide in certain of its features, but the evidence that it is a 

 slide is not satisfactory, and it is not improbably a sink of the 

 surface due to the more recent movements of these intersecting 

 faults. 



Later Accumulations. — After these disturbances the accumula- 

 tion, both lacustrine and volcanic, continued, and there remain to be 

 considered three distinct formations to complete what is left of the 

 record of the uplifting of the Canon trough. These are a thick 

 bed of basic volcanic tuff with some conglomerate, a series of 

 basalt flows, and a rhyolite agglomerate and tuff. 



Between the period of disturbance and these later additions to 

 the accumulation there was, however, an interval of erosion in 

 which the inequalities due to the faulting were in some measure 

 reduced, particularly where the faults affected the softer formations. 

 This is inferred from the comparatively even surface upon which 

 the formations mantling the fault repose. In other places, as on 

 the north side of Strawberry Canon, the lowest of the three forma- 

 tions which succeeded the faulting is locally much thicker than 

 elsewhere, as if it occupied a ravine in the surface upon which it 

 was deposited. 



