454 



DILLER AND STANTON — THE SHASTA-CHICO SERIES. 



- = shoreline at close of the Horsetown 



epoch. 



- = shoreline at close of the Chico epoch. 



Figure 1. — Map showing approximately the Coast- 

 lines at Close of Horsetown and Chico epochs. 



in the central portion of the state. 

 There is evidence of the presence 

 of the Horsetown beds at Benicia, 

 for at that point Ammonites batesii, 

 which is one of the characteristic 

 fossils of the lower portion of the 

 Horsetown; beds, has been found. 

 The Knoxville beds evidently ex- 

 tend farther to the southward, even 

 as far southward as San Luis Obispo, 

 where Mr Turner* has found Au- 

 cella, but they do not appear to 

 reach the Santa Ana range of 

 southern California, where Mr Fair- 

 banks f reports that the Uj)per Cre- 

 taceous rests unconformably on 

 the metam Orphic rocks, in which, 

 according to him, fossils, probably 

 Carboniferous, have been found. 

 Farther southward only Chico fos- 

 sils have been found, as far as yet 

 definitel}^ known, extending in that 

 direction through Lower California 

 to near the 29th parallel and per- 

 il a[)S even farther. There is evi- 

 dence in this distribution of the 

 Knoxville, Horsetown and Chico 

 beds to^ the southeastward along 

 the coast of southern California 

 that the continent was subsiding 

 in that direction, as it was to the 

 northward, at least as far as Queen 

 Charlotte islands. 



The varying thickness of the 

 formations furnishes corroborative 

 evidence. The Knoxville, Horse- 

 town and Chico beds all diminish 

 in thickness to the northward from 

 Elder creek; the Knoxville from 



*U. S. Geol. Survey, Monograph xiii, p. 381. 



t Am. Jour. Sci., vol. xlv, p. 478. Fairbanks suggests that, although no lower Cretaceous has yet 

 been recognized in southern California, certain local fossiliferous beds on the summit of the Carrejo 

 mountains, 70 miles east of Sau Diego, may be of that age. 



