Keyes — Devonian & Carbonifero7is in Upper Mississippi Valley. 361 



Nearly all of the strata are highly fossiliferous. The verti- 

 cal section and the exposures are so extensive for a single 

 locality that the facilities for determining the exact range of 

 the various faunas stand unrivaled in the whole region. 

 Moreover, a key to the stratigraphy of the entire province is 

 furnished. Owing to unusually favorable opportunities for 

 forming extensive collections of the fossils which are rep- 

 resentative of the different horizons, the results are very com- 

 plete. The determination of the faunal zones and their most 

 important relationships as bearing upon the stratigraphy of 

 the region is therefore of great interest. 



In considering the faunal features of the succession the 

 chief interest centers in the nature of the fauna of the Kin- 

 derhook as a whole, and of each of its several parts. The 

 three most prominent considerations are: (1) the general 

 facies of the fauna in its entiretv, and the elements ffivingr it 



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its predominant features, (2) the character and genetic rela- 

 tions of the basal fauna, and (3) the upper limit, if any can 

 be clearly made out, of the fauna most characteristic of the 

 formation. 



1. Heretofore the custom has always been to treat the or- 

 ganic remains contained in the •* Kinderhook," *♦ Chouteau," 

 or •' Chemung " as belonging to a single fauna. Owing to the 

 heterogeneous beds that have been placed together, it has been 

 the chief mission of later work to take out from time to time 

 the various incongruous parts which were originally correlated 

 with this formation. Thus, gradually, at its typical localities 

 the terrane has finally come to be more clearly understood. 



The fauna contained in the threefold *♦ Kinderhook " when 

 deprived of those elements which are in reality wholly foreign, 

 presents a very different facies from that generally ascribed 

 to it. In the light of definite zonal distribution of the organic 

 forms there appear to be, instead of a single compact and 

 characteristic group of forms, two very distinct faunas. This 

 is nowhere more clearly shown than at the locality which may 

 be regarded as typical and in which the fauual zones have 

 been determined with considerable accuracy and corroborated 

 by evidence from other districts. It is owing to the indefinite 



