112 IOWA ACADEMY OF SCIENCES. 



character. Referring to terranes, the name would apply 

 to the lowermost member of the Mississippiaii series. 



The fauna which is generally thought to be the fauna 

 from the original Chouteau limestone is at best a fancied 

 medley of shadowy definition. Practically no detailed 

 work has yet been published. Careful determination of the 

 exact horizons of the various forms has not even been 

 attempted. Of the species described from the original 

 Chouteau of central Missouri many are now known to be 

 from formations other than the terrane under considera- 

 tion. It is small wonder, therefore, that the Chouteau or 

 Kinderhook fauna as we have so long known it is 

 apparently ill-defined, anomalous and puzzling. In the 

 critical study of the lowest Carboniferous faunas of the 

 Mississippi valley there is need, before all else, of exact 

 determination of the various organic forms that occur in 

 the original Chouteau limestone of central Missouri. It 

 is only with this type fauna that the faunas of the Kinder- 

 hook from other localities and other horizons can be com- 

 pared with profit. Until the fossils from the original 

 Chouteau are carefully collected and studied anew in their 

 entirety the "Choteau fauna" must be regarded as a 

 quantity unknown. 



