CHAPTER III. 

 BIOLOGICAL RELATIONS OF FOSSILS. 



Proper discrimination between similar fossil forms is very 

 essential to the thoroagh understanding of the rocks of a local- 

 ity. For through the means of the ancient forms of life the 

 geological age of the sediments under consideration is inferred. 



The importance of adequate representations of the lead- 

 ing fossils in an area exposing the strata to be investigated, 

 either for scientific interest or economical purposes, cannot, 

 therefore, be overestimated. 



In glancing over the list of fossils herein recorded, one is 

 impressed at once with the rich and varied character of the 

 faunas found within the limits of the state of Missouri. The 

 upper Paleozoic rocks, especially, are perhaps more prolific in 

 the remains of ancient life than in any other like district within 

 the Mississippi basin. Not only are the species numerous but 

 individuals are exceedingly abundant, locally, as well as through- 

 out the state, wherever those rocks are exposed. 



Aside from the practical and geological interest these fos- 

 sils possess, they offer unusually favorable opportunities for 

 biological studies — -the evolution and succession of particular 

 types and groups ; and the geographic distribution of species 

 in very ancient times. 



It is to be regretted that this phase of the subject could 

 not have been taken up more fully at the present time ; but 

 the unusual and unexpectedly large amount of material that had 

 to be examined necessitated the postponement of this treat- 

 ment to another time. Much valuable information has accumu- 

 lated for further faunal studies, and this will be incorporated 



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