CHAPTER II. 

 THE MAKING OF THE GEOLOGICAL TIME-SCALE. 



The Heterogeneous Names now in Use. — A critical examina- 

 tion of the nomenclature applied to the several divisions of 

 the geological scale reveals a strange mixture of names, the 

 reason for which is not evident to modern students of the 

 science. In the list of system-names we find Carboniferous 

 and Cretaceous, indicative of mineral characters, associated 

 with Tertiary and Quaternary, meaning rank in some unde- 

 fined order of sequence. The presence of these terms is no 

 less mysterious than the absence of grauwacke and old-red 

 sandstone, and primary and secondary, which were originally 

 included. Triassic is the name of another system and records 

 the threefold division of the system of rocks to which it was 

 applied ; and Devonian, the name of another, reminds us of 

 the county in England in which its rocks were first named. 

 Observing these things, one is tempted to call in question the 

 reliability of a systematic classification so heterogeneously 

 compounded. 



Importance of a Systematic Classification. — Although the older 

 living geologists can remember back almost to the beginnings 

 of the science, those who now are beginning their study of 

 geology may find profit in examining the foundation prin- 

 ciples, and the systems which have been devised and have 

 led to the construction and belief in the present classification 

 — a classification the adoption and unification of which has 

 been thought worthy of the organization and continuance of 

 an international Congress of Geologists. It is needless to call 

 attention to the necessity of some systematic classification of 

 geological formations, but as a foundation for the scientific 

 study of the history of organisms there is need of a time-scale 

 running back into the past, the degree of accuracy of which 



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