JUBASSIC LOCALITIES AND FArXA. 251 



500 yards north of the Sonora stage road. It has been known for several 

 years, but the only published mention of it was made recently by H. 

 W. Turner,^ who notes the occurrence of aucell?e and ammonites in the 

 slates. In 1893 James E. Mills sent to the writer some fossils from 

 this locality, including an Aucella, a Pecten, an ammonite and fragments 

 of wood. 



In November, 1893, the writer visited the region and noted that east 

 of Copperopolis is a large thickness of diabase-tuff, interbedded with 

 crystalline limestone, which is best seen about four miles east of Cop- 

 peropolis. The limestone strikes northwest-southeast, and shows traces 

 of fossils, but they could not be determined. East of the diabase-tuff 

 and limestone is a considerable thickness of serpentine, and still further 

 east is a thickness of several hundred feet of finely laminated slates, 

 interbedded with conglomerates and some serpentine. On the stage 

 road to Sonora about six miles east of Copperopolis and on the east 

 slope of Bear mountain are found a few aucell?e, and in the valley, at 

 the Texas ranch locality previously described, the slates are seen again 

 in places with many fossils — lamellil)ranchs and cephalopods. The 

 fauna is a very interesting one and characteristic of Upper Jurassic and 

 of either Corallian or lower Kimmeridge age. 



List of Fossils. — The following is a systematic list of the fossils found 

 here : 



BRACHIOPODA. 



Rhynchonella, sp. 



One specimen, not in a condition to figure, seems to present the char- 

 acteristics of Rhynchonella, but is so flattened that no certain deter- 

 mination could be made. It resembles somewhat Rhynchonella myrlna, 

 Whitfield. Geology of the Black Hills of Dakota, p. 347, pi. Ill, figs. 

 6,7. 



LAMELLIBRANCHIATA. 



Am.Hssium (EaioUum) aurarmm, Meek. Geol. of California, vol. i, p. 478, 



pi. I, fig. G. 

 Lima, sp. 



A small Lima, with heavy, radiating ribs, was found, Init could not be 

 determined specifically. 

 Aucella erriiigtom, Gabb. 

 Limu erringtoni, Gabb. Proc. California Acad. Sci., November, 1864, p. 



173. 

 Aucella erringtoni, Gabb, F. B. Meek. Geol. of California, vol. i, p. 479, 



pi. I, figs. 1, 2, 3, 5, 7. 



* Am. Geologist, May, 1893, p. 308. 

 XXXV-Rur,r,. GEor, Soo. Am., Vor,. 5. 1893. 



