58 G. C. Broadhead — Cambrian and the Ozark Series. 



series and stated that the second Magnesian limestone and the 

 other series below to the Archaean seem to correspond with 

 the description and position of beds referred by Mr. Walcott 

 to the Upper Cambrian. I now make the additional state- 

 ment that there is a similarity in character and composition of 

 the entire series from the top of the first Magnesian to the 

 lowest member of the Ozark series so as to make it seem 

 proper to class the various members in one series the " Ozark 

 Series." 



The author of the article on the Cambrian and Ozark Series 

 published in this Journal for March, 1893, would make us 

 believe that he was the first person who had suggested the 

 appropriateness of assigning this series to the age of the Cam- 

 brian, but as I have above stated the Cambrian age had been 

 suggested before. Again, referring to Bulletin, JS"o. 81, Corre- 

 lation papers, Cambrian, Mr. Walcott says that " The Cambrian 

 rocks occur in the southeastern portion of the State, about the 

 Ozark Uplift. In several other places in the same Bulletin 

 the Cambrian and Potsdam of Missouri are referred to. In 

 the article above referred to, published in this Journal for 

 March, 1893, a statement is made on pages 221 and 222 that in 

 view of the recent work of the Missouri Geological Survey a 

 new classification would be necessary. If necessary, it would 

 be either for correction of former work done, or else on 

 account of new discoveries. I do not consider that previous 

 or present facts can justify any particular change. 



Prof. Swallow defined the Magnesian limestone series (Ozark 

 Series) and gave names to the principal beds in their order 

 thus : 



First Magnesian limestone. 



First or Saccharoidal sandstone. 



Second Magnesian limestone. 



Second sandstone. 



Third Magnesian limestone. 



Third sandstone. 



Fourth Magnesian limestone. 



The original section is in the main correct. Still there are 

 certain beds found in one part of the State that cannot be 

 entirely differentiated at other localities and some beds found at 

 one place may be wanting at other places. Prof. Swallow 

 recognized a third and a fourth Magnesian limestone on the 

 Osage. The formation known as the Third Magnesian lime- 

 stone includes certain beds which cannot be distinguished from 

 the fourth Magnesian and it may be that the lower limestones 

 of Madison County are of the age of the fourth Magnesian ; if 

 so, the two are not separated by a sandstone in Southeast 



