Geol.— Vol. II.] ANDERSON— CRETACEOUS DEPOSITS. 9 



result has been a revision and reclassification of the Creta- 

 ceous deposits, and the publication of some surprising facts 

 connected with their occurrence and deposition. The 

 astonishing thickness of these sediments in their deep- 

 est section seems almost incredible, especiall}' when one 

 considers the limited dimensions of their basin, and the enor- 

 mous movements necessary for their formation and subse- 

 quent folding. According to the estimates of these writers, 

 about thirty thousand feet of sediments accumulated in the 

 basin of the Sacramento without the intervention of any 

 great disturbances, and during a period of continuous and 

 prolonged subsidence. They have accordingly included 

 in a continuous series all the strata of wKat is called the 

 Shasta-Chico series, embracing the Chico, Horsetown, and 

 Knoxville, and including rocks below the lowest Aitcella- 

 bearing horizon. They recognize faunal changes in the 

 series, but no decided breaks. 



Dr. T. W. Stanton (1895) published an extended list 

 of Knoxville species, obtained from beds in the Shasta- 

 Chico series below the upper limit of the range of the genus 

 Aticella. More than fifty species are added by this con- 

 tribution to the fauna previously known as belonging to this 

 division. These species occur mainly in the upper portion 

 of the Knoxville, within three thousand feet, stratigraph- 

 ically, of what is believed to be the upper limit of the 

 range of Aucelhi. 



From a more recent paper by the same author (Stanton, 

 1897), it would appear that the Knoxville strata are to be 

 correlated with the Comanche series of Hill, including the 

 Trinity and Washita divisions. The Cretaceous series of 

 California, south of Tehama County, has been less studied, 

 but seems to be less simple than it is at the north. 



Fairbanks has reported in the neighborhood of San Luis 

 Obispo a distinct unconformity between Atice/Za-hearing 

 and Chico strata. 



It has also been shown by both Stanton (1895, 1895-96) 

 and J. C. Merriam (1897) that the Martinez Group of Gabb 

 consists of two parts, one indistinguishable from the Chico, 



