510 HISTORY OF GEOLOGY. 



several steps in generalization and classification, before it could take 

 place. Still such attempts were made. In 1743, was published, A 

 new Philosophico-chorographical Chart of East Kent, invented and 

 delineated by Christopher Packe, M.D. ; in which, however, the main 

 object is rather to express the course of the valleys than the materials 

 of the country. Guettard formed the project of a mineralogical map 

 of France, and Monnet earned this scheme into effect in 1780,? " by 

 order of the king." In these maps, however, the country is not con- 

 sidered as divided into soils, still less strata ; but each part is marked 

 with its predominant mineral only. The spirit of generalization which 

 constitutes the main value of such a work is wanting. 



O 



Geological maps belong strictly to Descriptive Geology ; they are 

 free from those wide and doubtful speculations which form so large a 

 portion of the earlier geological books. Yet even geological maps 

 cannot be usefully or consistently constructed without considerable 

 steps of classification and generalization. When, in our own time, 

 geologists were become weary of controversies respecting theory, they 

 applied themselves with extraordinary zeal to the construction of strati- 

 graphical maps of various countries ; flattering themselves that in this 

 way they were merely recording incontestable facts and differences. 

 Nor do I mean to intimate that their facts were doubtful, or their dis- 

 tinctions arbitrary. But still they were facts interpreted, associated, 

 and represented, by means of the classifications and general laws which 

 earlier geologists had established ; and thus even Descriptive Geology 

 has been brought info existence as a science by the formation of sys- 

 tems and the discovery of principles. At this we cannot be surprized, 

 when we recollect the many steps which the formation of Classifica- 

 tory Botany required. We must now notice some of the principal 

 discoveries which tended to the formation of Systematic Descriptive 

 Geology. 



8 Atlas et Description Mineralogique de la France, entrepris par ordre du Rot; 

 par MM. Guettard et Monnet, Paris, 1780, pp. 212, with 31 maps. 



