CHAPTER VII. 



THE LOWER CARBONIFEROUS OR MISSISSIPPIAN SERIES: THE 

 DEVELOPMENT OF THE NOMENCLATURE, AND CLASSIFICATION 

 OF THE LOWER CARBONIFEROUS FORMATIONS OF THE MISSIS- 

 SIPPIAN PROVINCE. 



The presence of the Carboniferous system in America was early rec- 

 ognized by finding coal beds containing plants similar to those of the 

 Coal Measures of Europe ; but the determination of the lower and 

 upper limits and the classification of the Carboniferous formations 

 were matters of gradual development. 



In the northern and central portions of the Appalachian province 

 the interval between the marine Devonian formations and the Coal 

 Measures is mainly filled by arenaceous deposits with few distinguish- 

 ing fossils, and here the more interesting correlation problems were 

 concerning the termination of the Devonian. 



In the Mississippian province the sedimentation introducing the Car- 

 boniferous was strikingly different. A considerable series of lime- 

 stones and calcareous shales, and a few sandstones intervene between 

 the termination of the Silurian and the base of the coal-bearing strata 

 above. These rocks contain rich and varied fossil faunas, and their 

 correlation and classification constitute one of the most important 

 chapters in American geology. Rocks containing Devonian faunas are 

 found at the base of the series in some parts of the province, but in 

 other sections they are missing. The formations resting upon the De- 

 vonian where these occur, and in other places upon the Silurian, are 

 characterized by fossils of Carboniferous age, and have heretofore gone 

 under the names u Mountain limestone,' 7 " Carboniferous limestone," 

 " Subcarboniferous," and "Lower Carboniferous." No one of these 

 names is satisfactory, and as these formations are bound together by a 

 common general fauna and constitute a conspicuous feature in the 

 geology of this region, it is proposed to call them the Mississippian 

 series. This series may be defined stratigraphically as that series of 

 rocks, prevailingly calcareous, which occupies the interval between the 

 Devonian system and the Coal Measures, and is typically developed in 

 the States forming the upper part of the valley of the Mississippi 

 River, viz, Missouri, Illinois, and Iowa. The name is a slight modifica- 

 tion in form and usage of a name proposed by Alexander Winchell in 

 1870. 1 



1 The Marshall group, etc., Am. Phil. Soc, Proa, vol. 11, p. 79. 



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