Geol.— Vol. II.] ANDERSON— CRETACEOUS DEPOSITS. 47 



statements, that all of these scattered localities contain 

 strata entirely equivalent to that of Paskenta, since below 

 this horizon in the sections of the Sacramento Valley no 

 ammonites have thus far been discovered. This horizon, 

 moreover, represents exactly and completely all that should 

 be included in the Knoxville as it w^as first described by 

 White (18S5). 



Three things should be noticed regarding the Knoxville 

 horizon as thus understood, showing its faunal relations to 

 that of the Horsetown, First, it is characterized by an 

 almost distinct fauna, very few species of which appear to 

 have been found in the Horsetown portion of the series, 

 while in each the total number of species is rather large. 

 Second, the typical and varied Horsetown fauna occurs 

 very near, though above, the upward limit of the Knoxville, 

 and appears there in a somewhat striking contrast with it. 

 The transition is sudden. Third, the Horsetown fauna, 

 with the exception of three or four species already men- 

 tioned, does not seem to have been, and hardly could have 

 been derived from that of the Knoxville. The types are 

 entirely different. Dr. White believed the Knoxville fauna 

 to be decidedly boreal in character, and referred particu- 

 larly to the genus Aticella in support of this view. The 

 same opinion has been held by others, and Dr. J. P. Smith 

 states that some of the ammonites have their nearest alHes 

 in the north of Europe. Reference has already been made 

 to the equally manifest tropical aspect of the fauna of the 

 Horsetown. 



Another circumstance that appears to coincide with this 

 faunal demarcation, and which forms a strong corrobora- 

 tive testimony in support of the conclusions to be drawn 

 therefrom, will be discussed later in connection with the 

 distribution of the Horsetown beds and the general occur- 

 rences of intrusive peridotites. 



The Sub-Knoxville Horizon. 



One of the most important contributions made by Diller 

 and Stanton to our knowledge of West Coast geology was 

 in the discovery of an immense thickness of strata below the 



