1 82 THE JOURNAL OF GEOLOGY. 



fication took little or no account of actual time -factors in 

 geology. 



Lehmann^ (Johann Gottlob Lehmann died in St. Petersburg, 

 1767) is generally credited with having first proposed a classifi- 

 cation of rocks on the basis of the order of their formation, as 

 Primitive, Secondary, and a third class, the modern or superficial 

 rocks made by the deluge or ordinary river action. Lehmann 

 recognized also a direct relation of origin of the Secondary from 

 the Primitive rocks, and thus arose the beginnings of the geo- 

 logical time -scale. Lehmann recognized three originally dis- 

 tinct kinds of rocks, or rock formations. The volcanic were 

 separated from the others because having no particular connec- 

 tion with either in origin. The distinction, however, between 

 Primitive and Secondary was fundamental. The Primitive was 

 strictly the original, basal rock formed by crystallization from 

 chemical solution before organisms lived ; and the Secondary 

 rocks were of secondary origin, made out of fragments of the 

 older and always lying above them. In the original classifica- 

 tion of Lehmann, Secondary included all the stratified rocks, as 

 we now consider them, and in the classifications following Leh- 

 mann for some years the term Secondary was applied, though in 

 a restricted sense. 



Cuvier and Brongniart proposed the name Tertiary for the 

 rocks classified as Secondary by Lehmann, but lying above what 

 is now known as the Cretaceous system ; and Quaternary was 

 introduced by Morlot in 1854 for the rocks of superficial posi- 

 tion and of glacial or fluviatile origin. Thus the nomenclature 

 of Lehmann, which was proposed originally to indicate the deri- 

 vation of the Secondary from the Primitive, was expanded -on 

 the basis of stratigraphic succession, and we observe the anomaly 

 of a retention of two names (Tertiary and Quaternary), formed 

 on the principle of Lehmann's terms, but his own terms, as well 

 as his theory as a basis of classification, entirely discarded. 



'J. G. Lehmann, Versuch einer geschichte von floetz-gebiirgen, etc., Berlin, 1756. 

 French translation cited by Lyell. Essai d'un Hist. Nat. des Couches de la Terre, 1759. 

 See Lyell," Principles," Vol. i, p. 72, and Conybeare and Phillips "Geology," p. vi, and 

 p. xlii. 



