642 E. O. ULEICH REVISION OF THE PALEOZOIC SYSTEMS 



The facts are essentially the same in the western or Wichita uplift. 

 Eesting on the Eeagan, the Arbuckle begins with beds holding the same 

 possibly late upper Cambrian trilobites mentioned as occurring at the 

 base of the formation in the Arbuckle uplift, and the next faunal zone is 

 undoubtedly Canadian. 



Judging from the facts in hand^ it seems unlikely that the Ozarkian 

 period is extensively represented in Oklahoma. Even the small inlier of 

 old cherty rocks, which comes to the surface in a structural dome cut 

 through by Spavinaw Creek, near the eastern border of the State, and in 

 which I at first thought I recognized a late Jefferson City fauna, proves 

 on closer examination to contain nothing but Canadian fossils. 



In central Texas. — The Eopaleozoic section in central Texas begins 

 with an upper Cambrian section that is in every respect comparable with 

 the deposits of the same epoch in south-central and southwestern Okla- 

 homa. This agreement seems to pertain also to the overlying dolomite 

 and limestone, this part of the section being, so far as it goes, practically 

 the same as the Arbuckle limestone in Oklahoma. The limestone series 

 is much thinner than in the Arbuckle Mountains section in Oklahoma, 

 the upper 3^000 feet of the Arbuckle limestone as developed there beings 

 unrepresented ; but in thickness, lithologic features, and beds represented 

 the Texas section agrees ver}^ well with the section shown in the Wichita 

 Mountains uplift. The dolomitic "marble" bed, which, with accompa- 

 nying thinner limestones carrying trilobites, constitutes the basal division 

 of the Arbuckle limestone in Oklahoma, was clearly recognized in the 

 vicinity of Marble Falls, in Burnet County. This part of the section 

 may be Ozarkian, but neither the trilobites nor the lithologic character 

 and sequence of the beds suggests any established Ozarkian formation 

 with which it might be correlated. Provisionally it seems advisable to' 

 place these beds as late upper Cambrian. 



Following the "marble" series, but locally apparently overlapping it,. 

 so that it comes into contact with the Honey Creek member of the Rea- 

 gan, are magnesian and relatively pure, fine-grained, and more or less 

 cherty limestones that are most certainly of Canadian age. This con- 

 clusion, as will be shown later on, is based on unequivocal fossil evidence. 

 According to present evidence, then, it appears that the section in central 

 Texas, the same as the Arbuckle and Wichita mountains sections in Okla-^ 

 homa, contains no positively recognizable Ozarkian deposits. The same 

 is to be said of the Franklin mountains sections in western Texas. 



The Ozarkian in western North America. — Ozarkian deposits seem to 

 be wanting entirely on the eastern side of the Rocky Mountains province. 



