Geol.— Vol. II.] ANDERSON— CRETACEOUS DEPOSITS. 15 



The fossiliferous portion of this series has been divided 

 into three divisions, mainly upon faunal characteristics. 

 The lower nineteen thousand nine hundred feet contain an 

 abundance oiAucellce, of not more than two or three species, 

 several species of Cephalopoda and other mollusks, also 

 plant remains. This is the portion of the Cretaceous series 

 to which the name Knoxville has been appHed. 



Stanton placed the upper Hmit of the Knoxville at the 

 upper limit of the range oi Aiicella. Mr. Diller (1893, p. 

 211) at one time stated that in the lower nineteen thousand 

 nine hundred feet of the Elder Creek section the only fossil 

 found was Aucella; and in another paper Stanton says that 

 they are often so abundant in the strata that it would seem 

 they must have monopolized the bottom of the sea. Later, 

 however, Stanton (1895, pp. 11-85) pubHshed a large 

 number of species as belonging to the Knoxville, many of 

 which have come from the strata of this section or near it. 

 But it is to be noted that the entire list of molluscan and 

 cephalopod species added to the fauna of the Knoxville 

 from this section has been found almost if not entirely within 

 three thousand feet of the upper limit of the Knoxville, or 

 in other words, within this distance stratigraphically of the 

 upper limit of the range of Aucella. 



With the appearance of this new fauna at the top of the 

 Knoxville, as then defined, the number of AucellcB gradually 

 diminishes. This fact will be referred to further on. 



Above the upper limit of Aucella the shales continue 

 uninterrupted, though becoming more sandy, for about six 

 thousand feet, when they give place to conglomerates. It 

 is the sandy and conglomeratic portion, confined to the 

 uppermost four thousand feet of the series, that has been 

 referred to the Chico division; while between this horizon 

 and the Knoxville are the Horsetown strata. 



The section along Cottonwood Creek, Shasta County, 

 some fifteen or twenty miles north of Elder Creek, corre- 

 sponds closely with that already described in so far as the 

 series is represented. On the Cold Fork of the Cottonwood 



