IOWA ACADEMY OF SCIENCES. Ill 



tlie fossils are found chiefly in the upper layers of the 

 formation. Meek and W'orthen's collections are now 

 known to have been all made from layers within a few feet 

 of the bottom of the Burlington limestone. 



The fauna of Meek and Worthen's Kinderhook group is, 

 therefore, not the fauna of the whole of the three-fold ter- 

 rane which has long been known to geologists as the 

 Kinderhook, but it is the fauna only of the upper limestone 

 member — the Chouteau limestone. By them the fossils of 

 the lower two members of their Kinderhook were not con- 

 sidered in the least degree. To them, the lower faunas 

 were unknown. They delimited one geological sequence 

 lithologically. For the whole they defined faunally only 

 a very small part of the same sequence. They assigned a 

 definite geological age to the whole; when they were actu- 

 ally justified only in ascribing an age to a single member. 

 The Kinderhook fauna as we today know 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. 



This brings us to the question as to what is the Chouteau 

 stage. The biological geologists are inclined to apply the 

 term (Ihouteau to the earliest of the three categories into 

 which they subdivide the Eo-Carboniferous of the Mis- 

 sissippi 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. Broad- 

 head's subsequent extension of the title making it synony- 

 mous with Kinderhook does net appear to render it in any 

 way valid. 



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

 can only be made to apply to the stage of the Chouteau 

 limestone. In this sense it satisfies all the requirements of 

 dual classification in geology. Moreover, it may refer to a 

 fauna that is a compact unit. It applies to a fauna which 

 is believed to be Carboniferous. It eliminates the 

 incongruous elements which are not Carboniferous in 



