HOESETOWN BEDS. 205 



The Horsetown beds. — TliG llorsotowii hcxhi, US it seeuis convenient to call 

 the group wliich occurs near Cottonwood Creek, Shasta County, are con- 

 fined to that locality, so far as known, and their stratigraphical relation to the 

 Knoxville series is undeterniincd. The solution is very prohaldy to be 

 found in the eastern Coast lianges in Tehama County, but this region is not 

 known to have been geologically explored and it probably will not be ex- 

 amined until a special study of the Coast Kanges as a whole is undertaken. 

 The Horsetown beds are somewhat altered, but at the points visited by 

 Dr. White and mv^self they do not show the characteristic serpentiin'zation 

 and silicification of the metanior[)hosed Knoxville beds. It cannot l)v any 

 means be asserted definitely, however, that they were not involved in the 

 upheaval and metamorphism which took place after the Knoxville and be- 

 fore the Wallala [)eriod, because much of the Knoxville series is also little 

 altered. On the other hand, the Horsetown beds rest unconformably upon 

 the auriferous slates of that region, which are of uncertain age, though ap- 

 parently continuous with the Carboniferous of Pence's ranch Professor 

 Whitne)' detected this non-conformity, tliough expressing the result in some- 

 what guarded terms.^ The mining operations which have since been pros- 

 ecuted have so exposed the rocks as to leave no room for any possible 

 difference of ojiinion. The slates upon which the Plorsetown beds lie are 

 somewhat peculiar and differ physically from those of the Marij)Osa beds, 

 showing a very thin cleavage and an unusual, silver-gray luster. Tliey give 

 to the eye an impression of great geological age. The fauna of the Horse- 

 town beds includes the whole of Gabb's Shasta group, excepting the species 

 already enumerated as belonging to the Knoxville. Mr. Gabb and Dr. 

 White agree in considering the affinities of these fossils to be with those 

 of the Gault, and therefore decidedly later than the Knoxville series. 

 Though the Horsetown beds lie not far from the general line of the quick- 

 silver belt, they are not known to occur anywhere in close connection with 

 the ore deposits. 



The Cascade Range. — It is luirdly possiblc to Contemplate the close relation 

 shown to subsist between the eastern and western ranges of central Cali- 

 fornia without inquiring what connection, if any, exists between them 



' Geol. Survey California, Geology, vol. 1, p. 321. 



