210 University of California Publications in Geology [Vol. 7 



good example of the impossibility of practically applying the 

 faunal division idea, and the inconsistency to which the mixed 

 notion of faunal and formational unity of the Vaqueros may 

 lead. 



Puente Hills, Elclridge, 1907. — In the section on the Puente 

 Hills Oil District, 32 by Eldridge, a new term is introduced for 

 what is evidently the local representative of the Monterey series 

 — the Puente formation. This is said to be "the equivalent of 

 at least a part of the Modelo formation, and possibly including 

 some of the Vaqueros" (p. 103). 



The "Puente formation" is said to consist of 2000 feet of 

 shale, chiefly earthy but with minor siliceous layers and some 

 thin sandstone layers and limestone lenticles; followed by a 

 heavy bedded concretionary sandstone, 300 feet in the western 

 part of the hills, 1000 feet in the eastern portion ; and wanting 

 in the southern portion; then 300-400 feet of siliceous shale with 

 a few sandstone beds and quartzo-calcareous concretions. The 

 relations of this massive concretionary sandstone to the over- 

 and underlying shales suggests strongly the relation of the mas- 

 sive concretionary Modelo sandstone of the Santa Clara District 

 to it.'; over- and underlying shales. And its rapid thinning out 

 and perhaps disappearance towards the sea is remarkably sug- 

 gestive of the Modelo conditions. 



Eldridge hesitates to finally accept the equivalence of the 

 Puente to the "Monterey" (iising this in the sense of "Monterey 

 shaie" of Arnold, for example) because of "the marked litho- 

 logic similarity of portions of the lower division of the Puente 

 formation to certain strata in the Santa Clara Valley and else- 

 where in the Coast Range that have been determined by their 

 fossils to be lower Miocene and possibly Oligocene — lower than 

 the Monterey." Here again we have the formation-faunal stage 

 fallacy. Nevertheless "from geologic conditions to the south 

 of the Puente Hills in the Santa Ana Range, however, the writer 

 is inclined to consider the entire succession of beds described 

 above as the local equivalent of the Monterey. ' ' As in the Santa 

 Clara Valley, this series underlies the "Fernando formation" 

 unconformably. 



52 hoc. ext., pp. 102-137. 



