508 J^LIE DE BEAUMONT. 



France did not cease with its publication ; for the government, havhig 

 subsequently decreed the preparation of a more detailed geological 

 map, the direction of this work (of which the first portion was published 

 in 1874), was confided to De Beaumont. Even when in 18G8 he was 

 obliged by the rules of the service to resign his place as inspector- 

 general in the corps of mining engineers, he was still retained as 

 director of the detailed geological map, a duty with which he was 

 occupied up to the time of his death. Besides these official duties in 

 connection with his profession, he succeeded in 1835 his old master 

 Brochant de Villiers as professor of geology at the Ecole des Mines, 

 having already in 1832 been called to fill what was then the only 

 chair of natural history in the College de France, left vacant through 

 the death of Cuvier. Making this a chair of geology, he became 

 the great teacher of the science in France, and during twenty years 

 gathered around him students from every land, who learned to recog- 

 nize in Eiie de Beaumont the founder of a school. Plis " Le9ons de 

 Geolo"-ie Pratique," given at the College de France in 1843, and his 

 " Notice sur les Systemes de Montagnes " in 1852, resume the greater 

 part of his teachings. 



Elie de Beaumont early adopted the theory of elevation-craters of Von 

 Buch, which, not confining to volcanic naountains, he extended to moun- 

 tain chains in general, these being, according to him, connected with 

 eruptions of plutonic rocks, and having been thrown up in successive 

 a^es by violent and parox^-smal movements. All the lines of fracture 

 and elevation of the same date were supposed by Elie de Beaumont to 

 be parallel to a great circle of the earth, thus giving the basis for a 

 classification of mountains. The relative dates of these phenomena he 

 endeavored to fix by considering the respective ages of the disturbed 

 strata and the horizontal ones around them, thus determining the ago 

 of the various mountain chains. Finally, he attempted to show a 

 geometrical co-ordination of the mechanical forces which had thus dis- 

 turbed the earth's crust, and conceived that the lines of the various 

 systems of elevation were so arrapged as to form a pentagonal net- 

 work or reseau pentagonal. His studies on mountain systems, begun 

 in 1829, were continued with zeal up to the last years of his life, 

 involving great labors in the field and an enormous amount of trigono- 

 metrical calculation ; but his conclusions are rejected by most of the 

 ceoloijists of the present time. 



In 1847 appeared his remarkable essay Sur les Emanations Volca- 

 niques et jMetalliferes, in which, bringing to bear on the subject his wide 

 knowledge of chemistry and of mineralogy, Elie de Beaumont proceeded 



