278 C. R. KEYES— DEVONIAN INTERVAL IN MISSOURI 



forms. Meek and Worthen's Illinois collections are now known to have 

 all been made from layers within a few feet of the bottom of the Bur- 

 lington limestone. 



The fauna of Meek and Worthen's Kinderhook group is therefore not 

 the fauna of the whole of the three-fold terrane which has long been 

 known to geologists as the Kinderhook, but it is the fauna of only the 

 upper limestone member, the Chouteau limestone. By them the fossils 

 of the lower two members of their Kinderhook were not taken into con- 

 sideration to the least extent. To them the lower faunas were practically 

 unknown. In fact, they delimited a formation stratigraphically. For 

 the whole they defined faunally only a very small part of this formation. 

 They assigned a definite geological age to the whole when they were 

 actually justified in ascribing an age to a single member. The Kinder- 

 hook fauna, as we have long known it, is in reality only the fauna of the 

 Chouteau limestone. We know now that other and very different faunas 

 occur in the shales and limestones immediately underneath the Chouteau 

 limestone. 



CHOUTEAU STAGE 



The biological geologists are inclined to apply the term Chouteau to 

 the earliest of the three faunal categories into which they subdivide the 

 Eo-Carboniferous of the Mississippi valley. The title thus refers to the 

 Kinderhook terrane of Meek and Worthen. Before the application of 

 the term in this sense the name had already been formally given to the 

 upper member of the Kinderhook* Broadhead's subsequent extension f 

 of the title making it synonymous with Kinderhook does not establish 

 its validity. 



Chouteau, if it is to be retained as a faunal term in geology, can only 

 be made to apply to the stage represented by the original Chouteau lime- 

 stone. In this sense it satisfies all the requirements of dual classifica- 

 tion in geology. Moreover, it may refer to a fauna that is a compact 

 unit. It eliminates, as will hereafter be shown, the elements which are 

 not Carboniferous in character. 



Referring to terranes, the name would apply to the lowermost member 

 of the Mississippian series. 



The fauna which is generally thought to be the fauna from the orig- 

 inal Chouteau limestone is at best a fanciful medley of shadowy defini- 

 tion. Practically no detailed work has yet been done that is published. 

 Careful determination of the exact horizons of the various forms has 

 not even been attempted. Of the species described from the original 



* Missouri Geol. Survey, 1st and 2d Ann. Repts., 1855, p. 103. 

 f Ibid., Rept. 1873-74, 1871, p. 20. 



