COOPER LIMESTONE. 11 



represented in the section given on page 175, and it is not known 

 to occur at any other locality excepting where that section was 

 taken, and near there on the Blackwater. 



In composition it is a rather pure Limestone, and resembles 

 some of the more compact layers of the Chouteau above. It is 

 generally, however, more compact and heavy-bedded, and differs 

 in always having numerous small, irregular particles 'of calc- 

 spar disseminated through it. 



The fact that this rock occurs so frequently immediately 

 beneath the Chouteau Limestone in Cooper county, leads me 

 to place it provisionally in that position in the general section, 

 though I am aware further investigations may prove it to belong 

 even to some part of the Lower Silurian series. It is the only 

 bed observed in this county in regard to the relative position 

 of which there can be any doubt." 



The name Cooper was not used in the literature from Meek's 

 report in 1873 to 1916, when it appeared in an abstract of one 

 of the writer's papers. 



In 1905 F. B. Van Horn 1 mentioned middle Devonian de- 

 posits in Moniteau County and gave some details about dis- 

 tribution but no correlation data. He did not differentiate 

 sharply between the Cooper and the overlying Callaway though 

 he gave Ulrich's opinion that both middle and upper Devonian 

 were present. 



■ In 1908 Marbut mentioned the occurrence in Morgan County 

 of rocks supposed to be Devonian and described them as follows: 

 "The rock consists of very fine-grained massive compact bluish 

 limestone weathering to a white, color. It is so massive that the 

 weathering takes the form of the erosion of basins and holes in 

 the surface of the limestone rather than disintegration along the 

 bedding planes of the rock. Crinoid stems, brachiopods, and 

 other forms of fossil remains which are so abundant in the over- 

 lying Mississippian limestones are absent from this Devonian 

 rock. The only fossil found in it, at least without a very close 

 examination, is a loose growing compound coral which is very 

 abundant. 



The maximum thickness of this rock is probably not more 

 than 10 feet. In places it disappears entirely. It seems to be 

 merely a series of remnants of an originally very extended and 

 thick limestone formation which was nearly eroded away before 

 the deposition of the Mississippian limestone." 2 



'Mo. Bu. Geol. Mines, III, pp. 38-43. 



'Mo. Bu. Geol. Mines, 2nd series, VII, p. 49. 



