208 J. S. DILLER — GEOLOGY 01 CALIFORNIA AND OREGON. 



throughout tin; whole series. No definite discordance; could be made 

 out anywhere within the sections, and the slight irregularities could not 

 he identified in any two sections at the same horizon. There is good 

 reason, therefore, for believing that these irregularities are only local. 

 They are believed to be simply those of original continuous deposition 

 coupled with others that naturally arise in the deformation of a great 

 thickness of shales conformably interstratified with a much smaller pro- 

 portion of relatively thin conglomerates and sandstones. 



The conclusion derived at that time from a study of the stratigraphy 

 alone was that the Cretaceous formations from the base of the Knoxville 

 through the Horsetown to the top of the Chico form a continuous scries 

 of sediments, the deposition of which took place without a marked in- 

 terruption of any kind. At the same time it was fully recognized that 

 even absolute conformity * does not necessarily indicate uninterrupted 

 sedimentation, and that faunal continuity is essential to complete the 

 demonstration. Furthermore, Dr Becker reports an unconformity be- 

 tween the Chico and Shasta groups at several points on the ('oast range, 

 and considers it of great importance.! Mr H. W. Turner states | that 

 sections north of mount Diablo apparently show continuous deposition 

 • from the Neocomian to the Pliocene, inclusive. Nevertheless, from his 

 own observation, there and elsewhere, together with those of Mr Becker 

 and Dr White, he regards it as practically certain that there is an un- 

 conformity between the Chico and Knoxville beds. 



In none of the cases noted above have the authors been advantagously 

 situated to compare the faunal relations of the two groups. This 1 shall 

 now proceed to briefly consider. 



During the seasons mentioned many Cretaceous fossils were collected 

 from seventy-nine different localities in California and Oregon. Since 

 that time the collections have been greatly augmented from other local- 

 ities in Oregon by Mr W. Q. Brown, and in California by James Storrs 

 and the writer. 



The fossils were all determined by Mr T. W. Stanton || under the su- 

 pervision of Dr C. A. White. They kindly furnished notes on the age 

 of the fossils in each case, distinguishing only between the Shasta and 

 the Chico-Tejon. In some case's, of course, the age could be stated; in 

 others it was doubtful, but in most cases it, was given without reservation. 



When ari attempt was made to represent these determinations on a 

 map and draw the line between the Chico-Tejon and the Shasta, a serious 



♦ McConnel describes the Cretaceous as perfectly conformable on the lower Carboniferous or 

 upper Devonian. Geol. Survey of Canada, Annual Report, 1886, pari D, p. 17. 

 t Bulletin 19, U. S. Geol. Survey, 1885, p. 12; U. S. Geol. Survey Monograph xiii, 1888, p. 1S8. 

 1 Bull. Geol. Soc. Am., vol. 2, pp. 399-401. 

 || Recently Mr Stanton has carefully revised his earlier determinations. 



