Giraud-Soulavie 207 



contends that the difference between the fossils of different 

 countries is due not to a geographical but to a chrono- 

 logical cause. "The sea," he says, "produces no more 

 ammonites, because these shells belong to older periods or 

 other climates. The difference between the shells in the 

 rocks rests on the difference in their relative antiquity, and 

 not on mere local causes. If an earthquake were to sub- 

 merge the ammonite-bearing rocks of the Vivarais beneath 

 the Mediterranean, the sea returning to its old site would 

 not bring back its old shells. The course of time has 

 destroyed the species, and they are no longer to be found 

 in the more recent rocks." * 



The sagacity of these views will at once be acknowledged. 

 Yet they seem to have made no way either in France or 

 elsewhere. The worthy Abbe, though a good observer and 

 a logical reasoner, was a singularly bad writer. At the 

 end of the eighteenth century a wretched style was 

 an unpardonable offence even in a man of science. 2 

 Whatever may have been the cause, Giraud-Soulavie has 

 fallen into the background. His fame has been eclipsed, 

 even in France, by the more brilliant work of his successors. 

 Yet, in any general survey of geological progress, it is 

 only just to acknowledge how firmly he had grasped some 

 of the fundamental truths of stratigraphical geology, at a 

 time when the barren controversy about the origin of 

 basalt was the main topic of geological discussion through- 

 out Europe. 



We have seen that the distinctness, regularity, and 

 persistence of the outcrops of the various geological for- 



1 Op. cit. tome vii. (1784), p. 157. 

 2 D'Archiac, Geologic ct Paldontologie, 1866, p. 145. 



