DISTRIBUTION OF JURASSIC FOSSILS. 221 



fossils were found in a limestone. Mr Walcott, who examined the fossils 

 for me, reported that only one genus, viz, Chasleles, could be identified, 

 and from what is known of the rocks of that region he refers the lime- 

 stone to the Carboniferous. This horizon had long been known fur- 

 ther northward, near Bass' ranch, through the investigations of Trask 

 and Whitney. 



Pentagonal and round erinoid .stems have been discovered by James 

 Storrs in a limestone on Clear creek between Horsetown and Texas 

 Springs. Professor Hyatt regards them as Triassic and probably of the 

 same horizon as the Hosselkus limestone* 



At Texas Springs Mr Storrs found a limestone containing a large pen- 

 tagonal erinoid stem, a spirifer and other brachiopods which Professor 

 Hyatt regards as belonging within the Jura-Trias. The older rocks, 

 upon which the Cretaceous strata of the western and northern borders 

 of the Sacramento valley at the Pit river region rest with a conspicuous 

 unconformity, are at least in part Jurassic, Triassic and Carboniferous 

 in age. 



As bearing upon the general distribution of the Taylorville Jurassic, a 

 collection of fossils made by Professor Condon on the upper waters of 

 Crooked river, in the Blue mountains of Oregon, deserves mention. In 

 lithologic character and fossils Professor Condon's specimens appeared 

 to the writer to very closely resemble the Jurassic rocks of Taylorville. 

 Professor Condon kindly loaned the specimens to be sent to Professor 

 Hyatt, who confirmed this view and established another important 

 locality of Taylorville Jurassic 



The discovery of Jurassic fossils on Pit river synchronous if not iden- 

 tical with that of Taylorville has thrown new light on the pre-Cretaceous 

 elevation of the Klamath mountains and the Sierra Nevada. Concern- 

 ing some of these fossils Professor Hyatt says* they " include the same 

 association of forms as the Mormon sandstone fauna, and, although the 

 specimens are not all well preserved, I have little doubt that the rocks 

 from which they came were synchronous with the Mormon sandstone of 

 Taylorville." 



These Jurassic rocks were deformed and metamorphosed with the 

 Triassic. Carboniferous and other portions of the auriferous slates. 

 They are separated from the unaltered Cretaceous (Shasta-Chico series) 

 of that district by a conspicuous unconformity. The same unconformity 

 extends southwestward, by way of Bedding, Horsetown and Ono, along 

 the western side of the Sacramento valley, into Tehama county, Califor- 

 nia, and northward, by way of Yreka, Cottonwood creek and Ashland, 

 far into Oregon. It is evident, therefore, that a great upheaval and met- 



* Letter of October 4, 1802. 

 XXXIII— Bull. Geol. Soc. Am., Vol. 4, 1882. 



