-I Guettard' s Mineralogical Maps 23 



This early effort at mineralogical map -making was 

 merely the beginning of Guettard's labours in this depart- 

 ment of investigation. " If you will only let me have a 

 proper map of France," he used to say, " I will undertake 

 to show on it the mineral formations underneath." When 

 Cassini's map appeared, it enabled him to put his design 

 into execution. After incredible exertions, during which 

 he had the illustrious chemist Lavoisier 1 as an assistant, 

 he completed the mineralogical survey of no fewer than 

 sixteen sheets of the map. These labours involved 

 journeys so frequent and prolonged that it was estimated 

 that he had travelled over some 1600 leagues of French 

 soil. At last, finding the work beyond his strength, he left 

 it to his successor Monnet, by whom the sixteen maps and 

 a large folio of explanatory text were eventually published. 2 



It must be acknowledged, however, that Guettard does 

 not seem to have had any clear ideas of the sequence of 

 formations and of geological structure ; at least there is 



ogische Geographic der Chursdchsischen Lande. Eight tints are used to 

 discriminate granite, gneiss, schist, limestone, gypsum, sandstone, river- 

 sand, clay and loam ; and there are also symbols to point out the localities 

 for basalt, serpentine, etc. Palassou, in his Essai sur let Mintralogie des 

 Monts Pyrenees, Paris, 1781, gave a series of maps with engraved lines 

 and signs, and also a route-map of the part of France between Paris and 

 the Mediterranean, with the general mineralogical characters of each line 

 of route indicated by strips of colour. He thus distinguished by a green 

 line the granite rocks, by a yellow line the "schists," and by a red line 

 the calcareous rocks. He also indicated the presence of these various 

 formations by different symbols, among which was one for extinct 

 volcanoes, that figures in the Clermont region and also to the west of 

 Montpellier. The early map of Fuchsel (1762) will be subsequently 

 referred to. 



1 See on the subject of Lavoisier's co-operation, D'Archiac's PaUont- 

 ologie Stratigraphique, p. 290, andpostea, p. 210. 



2 Atlas et Description Mintralogiques de la France, entrepris par ordre 

 du Roipar MM. Guettard ct Monnet, 1780. 



