GEOL.-VOL. I.] SMITH— COMPARATIVE STRATIGRAPHY. 363 



Brock's Ranch, and the fossils proved to be typical and well- 

 preserved specimens of Psetido?nonotis subctrcula?'ts Gabb, 

 This is sufficient proof that the Californian section of the 

 Upper Trias is in accord with that observed in other parts 

 of the world. 



These Triassic limestones and slates extend from Brock's 

 Ranch on Pitt River northward about thirty miles, crossing 

 Squaw Creek west of Kelly's Ranch near the forks of 

 Squaw Creek. They were also found on Bear Mountain, 

 five miles southwest of Silverthorn's Ferry on Pitt River. 

 They are fossihferous almost everywhere, and are easily 

 traced, because the massive Hosselkus limestone usually 

 caps the ridges. The best collecting ground is about three 

 miles northeast of Madison's Ranch on Squaw Creek, and 

 also about a mile and a half east of Terrup-chetta (Cotton- 

 wood Flat) on Squaw Creek, six miles north of Madison's. 

 In order to find the collecting grounds it is only necessary 

 to go along the base of the cliffs until an outcrop of the 

 soft Trachyceras limestone is seen, then abundant fossils 

 may be obtained anywhere in this area. The structure is 

 quite simple, the ridges being usually east-dipping mono- 

 clines, and the stratigraphic position of each bed may be 

 determined without difficulty. 



The Humboldt Range. Our knowledge of the stratig- 

 raphy of the beds above the Middle Trias in the Hum- 

 boldt Range has been until recently exceedingly meager. 

 But W. M. Gabb (9) has cited from there " Ammonites'" 

 ra7nsmie7'i Gabb (not Hauer), '■'■Ammonites''^ homfrayi^ 

 and Pseiidomonotis subcircularis, all of which have since 

 been shown to be characteristic of the Upper Trias of Cali- 

 fornia, and not to be associated with Middle Triassic faunas. 

 The writer has recently made an extended journey in the 

 West Humboldt Range in Nevada, in the study of the stratig- 

 raphy of the Trias. The greater part of the massive 

 limestone of that region seems to belong to the Upper Trias, 

 as the Muschelkalk beds with their characteristic fauna lie 

 at the base of the Star Peak limestone. About eight hun- 

 dred feet above the uppermost beds of the Middle Trias the 



