462 STUDIES FOR STUDENTS 



California, Turner and Ransome describe 1 small patches of Tejon 

 sandstones capping the hills. " This rests almost horizontally 

 upon the nearly vertical edges of the Mariposa [Jura-Trias] slates. 

 . . . The sandstones are overlain to the west by the light col- 

 ored sandstones of the lone formation. The two series are 

 probably not absolutely conformable, as the lone transgresses 

 onto the rocks of the Bed-rock series farther west." Tejon 

 fossils are found in this formation. The Tejon is found in 

 Oregon in the valley of the Willamette River at Albany and at 

 other localities. Clark states that " The Tejon strata of Oregon 

 have been found in a few widely separated localities in the cen- 

 tral and northern portions of the state. The most southern yet 

 observed is Coos Bay." 2 But he cites no literature on the 

 the subject, and Diller, in his discussion of the " Coos Bay Coal 

 Field," 3 makes no mention of Tejon strata. 



The Astoria beds at the mouth of Snake River are regarded 

 as Oligocene. 



THE UMPQUA FORMATION. 



The Eocene described in the Folio of the Roseburg quad- 

 rangle, Oregon, rests directly upon an eroded surface of the Upper 

 Cretaceous (Myrtle) formation. 4 There are evidences of con- 

 siderable erosion in the region before the deposit of the Eocene 

 beds. This leads Diller to believe that Chico may have been 

 present and eroded away. Diller describes the Eocene sedi- 

 mentary beds under the names " Umpqua formation," from the 

 Umpqua River on which the outcrops occur : " Wilbur tuff- 

 lentils;" and "Tyee sandstone." The most extensive and 

 important of these is the Umpqua. It lies unconformably 

 upon Cretaceous rocks, and " stretches far beyond the Rose- 

 burg quadrangle and plays an important role in the makeup 

 of the whole country west of the Cascade Range." The 



J Geol. Atlas of U. S., Sonora Folio, Calif., 1897. 

 2 U. S. Geol. Surv., Bull. 83, p. 103. 



3 Nineteenth Ann. Rep. U. S. Geol. Surv. for 1897-8, Part III, Economic Geol- 

 ogy. P- 3°9 et seq. 



4 Diller : Geol. Atlas U. S., Roseburg Folio, Ore., 1898. 



