52 



University of California Publications. 



[Geology 



Eocene fossils are said to have been found near Arbuckle, but 

 the locality is not known to the writer. Eocene strata may under- 

 lie the San Pablo ( ?) gravels and sandstones east of Capay Valley 

 in the portion left blank on section AB. 



As far as physical resemblances go, the Cretaceous exposed 

 at Rumsey is exactly similar to that near Knoxville, with the 

 possible difference that it may have a large proportion of sand- 

 stone and less shale. A magnificent section is exposed along 

 Cache Creek across the strike of the beds for several miles, and 

 the writer was not able to find any conglomerate beds or impor- 

 tant changes in sedimentation to suggest the presence of Chico. 

 Prom lack of palaeontological evidence, however, he has not ven- 

 tured to call all this enormous accumulation of sediments Knox- 

 ville. 



In Section CD an even greater thickness of Cretaceous sedi- 

 ments is shown between Pleasant Valley and Wooden Valley. 

 This section represents certainly not less than five miles of strata, 

 as it dips steeply to the northeast the whole distance, and shows 

 no evidence of faulting. The Cretaceous of this section, as in 

 section AB, disappears to the east at Pleasant Valley under late 

 Tertiary gravels and sandstones, still with a northeasterly dip 

 and a Knoxville appearance, and for similar reasons the whole 

 series has been represented as Shasta-Chico. None of the mas- 

 sive, thick-bedded, cavernous sandstones so characteristic of the 

 Eocene was observed. Becker* believed these strata to be of the 

 same age as the Franciscan, considering the latter to be a meta- 

 morphosed phase of the former, in which the "prominent char- 

 acteristics are the predominance of recrystallization, serpentini- 

 zation and silieifieation. " 



Contacts between Knoxville and Franciscan at many places 

 are now known, which show an unconformity existing between 

 the two formations. No better illustration of this can be seen 

 than at Berkeley. Here unmistakable Knoxville shales and sand- 

 stones containing aucellae may be seen along the lower slopes of 

 the hills between East and North Berkeley, resting at moderate 

 angles across the steeply pitching eroded edges of the various 

 Franciscan members. In both the sections AB and CD the Knox- 



*Mon. XIII, U. S. G. S. 



