Stratigraphic Catalogue of Missouri Fossils. 



BY CHARLES R. KEYES. 



The catalogue of fossils belonging to the various geological 

 formations of Missouri is based upon the report on the Paleon- 

 tology of the state which forms volumes lY and V of the sub- 

 ject reports. The arrangement is a zoological one, following 

 that in the report. 



In bringing together the ancient forms of life which flour- 

 ished during each geological epoch, there is at once brought 

 to notice a striking disparity in the distribution of the forms. 

 In some formations only a few organic remains are recorded ; 

 in others there is the greatest profusion. The unequal distribu- 

 tion is perhaps more apparent than real. A number of causes 

 lead to these results : First, and most important perhaps, is 

 the unequal search for fossils. Second is the unequal detec- 

 tion of the fossils. Third is the original irregularity in distri- 

 bution. Fourth is the numerical disproportion. Fifth is the 

 difference in preservation. Sixth is the inherent variation of 

 parts capable of retaining their original indentity. 



The disparity of search is one of those things which is 

 governed largely by chance. No effort of organized work can 

 overcome it. Local collectors spring up in certain places, and 

 for a long period of years carry on the work of accumulating 

 the fossils of the county or immediate locality with untiring- 

 zeal and energy. The result of their labors cannot be dupli- 

 cated in a generation, nor can their success be attained even 

 after years of constant and systematic application. As a mat- 

 ter of fact, then, an investigation of the paleontology of a 

 district is dependent largely upon the collections made by a 

 comparatively few persons scattered over the area, who have 

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