266 THE DEVONIAN AND CARBONIFEROUS. '[bull. 80. 



isfactory name, and in the county of Ste. Genevieve and on the eastern 

 and northeastern margins of the Ozark Uplift, above and below this 

 county, are found the typical outcrops of the individual formations 

 included in the group. 



This classification is used in reports already communicated to the 

 State geologists of Arkansas and Missouri, and I give it here to expose 

 the latest results of my attempts at correlation of these formations. 



One of the most important results which such a review of the history of 

 correlation emphasizes is the fact that all attempts to attain uniformity 

 of classification or nomenclature have failed to a greater or less extent. 



The extent of the artificiality of the correlation is in some measure 

 proportionate to the distance separating the formations compared ; but 

 the experience of the geologists of the second geological survey of Penn- 

 sylvania shows how difficult it is to make satisfactory correlations even 

 between the »ocks of adjoining counties. 



Amos Eaton, seventy years ago, attempted to make the classifica- 

 tion and nomenclature of the New York formations uniform with that 

 of Germany and England. He succeeded as well as anyone could in 

 his time ; but some young men, trained in his own school, went into 

 the field a few years later to work up the geology of New York State. 

 They began with the application of his system, but when they found 

 it fettering the accuracy of their observations they cast it aside. They 

 recorded the facts as they found them, gave independent names to the 

 formations for the purpose of identifying them, and formed a New 

 York system. 



The classification and nomenclature of this system has been adopted 

 as a standard in all respects except where uniformity with European 

 usage was attempted. 



The name "system" was lost because this is only part of a system; 

 the divisions, Ohamplain, Ontarian, Erian, etc., have been discarded 

 because they are purely artificial and have nothing to do with the 

 natnral classification of the rocks; the grouping of the formations into 

 Devonian, Silurian, is still allowed, but it is applied both loosely and 

 unsatisfactorily by all except the text-book user. After the New York 

 survey was completed, the same men, satisfied with their success, and 

 still remembering the philosophy of uniformity, thought it might be 

 applied to all American geology. They went westward, tried to fit the 

 New York and Pennsylvania systems to the geology of the Mississippian 

 province. In the cases where they attempted to classify the Mississip- 

 pian rocks on the Appalachian model the result proved unsatisfac- 

 tory, because artificial and not expressing the facts as they are. In the 

 cases where the nomenclature and classification have been built up inde- 

 pendently and strictly according to the local expression of the facts 

 they have been retained. 



One after another of these early attempts to produce uniformity in 



