CORALS FROM THE CHOUTEAU AND RELATED 



FORMATIONS OF THE MISSISSIPPI 



VALLEY REGION 



BY 



William H. Easton 



INTRODUCTION 



ARESTUDY OF THE ChOUTEAU CORALS 

 is important for the following reasons. 



1. The coral fauna of the Chouteau lime- 

 stone is larger in number of genera and spe- 

 cies than that known from any other Car- 

 boniferous formation in this hemisphere. 



2. The species are reestablished by crit- 

 ical restudy of the available primary types. 



3. The stratigraphic and geographic 

 ranges of the species are established by crit- 

 ical reexamination of previously published 

 records and restudy of specimens. Synony- 

 mies have been revised accordingly. 



4. Corals are so abundant in the Chou- 

 teau limestone that they are definitely useful 

 for correlation. 



5. The Chouteau is the oldest formation 

 of undisputed Mississippian age and it is 

 therefore important as a stratigraphic key 

 horizon. 



6. Further systematic study will be aided 

 by clarification of inadequately understood 

 genera and species. Some genera whose types 

 came from the Chouteau are known in 

 Europe and the Orient. 



7. The opportunity is presented to apply 

 modern systematics to a large number of 

 Lower Mississippian corals. 



The writer has studied every available 

 Chouteau coral known by him to be in in- 

 stitutional collections. Material which is 

 unavailable includes that not lent for study 

 by certain distant institutions, that stored 

 away during the uncertain times preceding 

 the war, and that which some institutions 

 have stored away because of lack of space. 

 If specimens are known to have been lost 

 or destroyed these facts are recorded. In 

 all, about 550 specimens have been studied. 



The check list included in this study 

 shows the occurrence of each species as de- 

 termined by the literature. It is to be hoped 

 that detailed collections will be made from 

 the Chouteau limestone (restricted) so that 

 the precise occurrence of the species may be 

 known. To that end this paper is offered as 

 an aid in stratigraphic studies of the Kinder- 

 hook group. 



The original descriptions of some species 

 are so inadequate or inexact that the species 

 cannot be recognized. Most of the original 

 descriptions require revision and the use of 

 modern morphologic terminology. 



Some of the Chouteau genera are known 

 to occur in Europe, Australia, and Asia and 

 a few of them possess such marked peculi- 

 arities that reasonable correlation of strata 

 can be made between these distant places. 

 Eventually, perhaps, the coral-bearing Car- 

 boniferous beds of America may be closely 

 correlated with the coral zones of western^ 

 Europe. 



Carboniferous corals are of undoubted 

 usefulness in stratigraphic correlation. Their 

 neglect for many years has probably resulted 

 from the generally indispensable necessity 

 of grinding one or more surfaces to ensure 

 identification. As a matter of fact, the grind- 

 ing of a surface on a coral is commonly 

 easier than the careful preparation of the 

 exterior or interior necessary for the precise 

 study of certain other fossils. 



Acknowledgments 



Specimens have been lent by: E. B. 

 Branson, of the University of Missouri; 

 Guy Campbell, of Corydon, Indiana; G. 

 Arthur Cooper, of the United States Na- 

 tional Museum ; Carey Croneis, of the Uni- 



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