MISSISSIPPIAN OF PHELPS COUNTY, MISSOURI 559 



In 1898 Broadhead, writing on the Ozark uplift and the growth 

 of the Missouri Paleozoic, 1 states that "beds of Chouteau lime- 

 stone" have been found in Wright and Maries counties, and that 

 the Burlington limestone has been recognized in Morgan, Benton, 

 and Hickory counties, from which he concludes that at least the 

 western half of the Ozark uplift was submerged during the Lower 

 Carboniferous period. 



The work of the present Missouri Bureau of Geology and Mines 

 has given some additional information concerning the distribution 

 of these deposits. Marbut, 2 Ball and Smith, 3 Van Horn and Buck- 

 ley, 4 and Lee, s working in different areas in the northwestern part 

 of the Ozark region, have mentioned these deposits, but up to the 

 present time no careful study has been made either of the distribu- 

 tion of this residual material or of its faunal content. In the litera- 

 ture it is commonly referred to as Chouteau or Burlington. In 

 some localities these deposits are termed "residual Boone Cherts." 



The purpose of the present paper is to present the results of a 

 careful study of the faunas contained in a number of these bowlders. 

 The bowlders which have furnished the material for this investiga- 

 tion were all collected within an area of about forty square miles 

 situated in the extreme northeastern part of the Rolla quadrangle 

 and the adjacent portion of Phelps County. 



This area is a small plateau the summit of which is capped by 

 resistant formations. The physiography and general geology 

 of the region have been well described by Lee 6 and need not be 

 rediscussed here. The entire plateau is underlain by the Jefferson 

 City dolomite of Canadian age, and lying unconformably upon 



1 G. C. Broadhead, "The Ozark Uplift and the Growth of the Missouri Paleozoic," 

 Missouri Bur. of Geol. and Mines, Vol. XII (1898), Areal Geology, p. 398. 



2 C. F. Marbut, "Geology of Morgan County," Missouri Bur. of Geol. and Mines, 

 Vol. VII (1907), 2d ser., pp. 49-51. 



3 S. H. Ball and A. F. Smith, "Geology of Miller County," Missouri Bur. Geol. 

 and Mines, Vol. I (1903), 2d ser., pp. 82-89. 



4 F. H. Van Horn and E. R. Buckley, "Geology of Moniteau County," Missouri 

 Bur. of Geol. and Mines, Vol. Ill (1905), 2d ser., pp. 44-58. 



5 Wallace Lee, "Geology of the Rolla Quadrangle," Missouri Bur. of Geol. and 

 Mines, Vol. XII (1913), 2d ser., pp. 41-43. 



6 Ibid., pp. 52-58, 13-40. 



