DELIMITATION OF THE ST. LOUIS 473 



lished by the French geologist^" in the publication of the Societe 

 Geologique de France. 



Just what were the exact vertical limitations assigned to the St. 

 Louis Limestone section by Englemann is not a matter of very clear 

 record. Other St. Louisians at that time used the term freely. 

 Most specific, perhaps, is Dr. Henry King. According to him^^ the 

 title covers the entire section between the Coal Measures and the 

 St. Peter Sandstone. The thickness of the formation is estimated 

 to be between 500 and 600 feet. Although King elsewhere mistakes 

 the St. Peter Sandstone for another sandstone lying at the base of 

 the Coal Measures he is still led to believe that there were repre- 

 sented 200 to 300 feet of the Carboniferous limestones, which, how- 

 ever, were found to carry Devonian fossils at the base. Therefore, 

 it may be considered that finally King included in his St. Louis 

 Limestone only those beds between the bottom of the Burlington 

 limestone and the base of the Coal Measures. 



Singularly enough when Englemann proposed the title St. Louis 

 Limestone it was generally believed that the formation which today 

 we know under this name rested upon the Kaskaskia limestone. 

 This belief was probably held by St. Louisians of that day for many 

 years, until Shumard finally demonstrated the true relations of the 

 two terranes. 



Inasmuch as Owen^- several years previously had restricted the 

 application of the term sub-Carboniferous to the section between 

 the top of the Devonian limestones and the base of the Coal IMeas- 

 ures, whereas prior to that time it had been made to include very 

 much more, even all below to the Blue, or Trenton (Galena), Lime- 

 stone, it is not improbable that the St. Louis geologists were en- 

 deavoring to fix the section to a restricted succession by giving it 

 a definite geographic title. In his Iowa work" Owen calls what is 

 now generally termed the St. Louis Limestone, at Keokuk, the Con- 

 cretionary Limestone; but he specifically correlates it with the 

 "Bedded Limestone of St. Louis." It was three years later that 

 Swallow'* and Shumard'^ at last restricted the term to the limits 

 now commonly accepted. 



At the time, therefore, when the title St. Louis Limestone was 

 proposed for a definite geological formation, and for a full decade 

 thereafter, it seems that the term covered approximately the early 



'"Bull. Soc. geol. de France, t. VI. p. 419, 1849. 

 uproc. American Assoc, Adv. Sci.. Vol. V, pp. 182-201, 1851. 

 i^Twenty-eighth Cong., 1st Sess., Sen. Doc. No. 407, pi. 3. 

 "Geol. Surv. Wisconsin, Iowa and Minnesota, p. 92, 1852. 

 "Missouri Geol. Surv., 1st and 2nd Ann. Repts., p. 4, 1855. 

 "Ibid., p. 170. 



