SYSTEMATIC DESCRIPTIVE GEOLOGY. 549 



order in the arrangement of these shells, certain 

 species lying in distinct bands 7 ." 



Such divisions as these required to be marked 

 by technical names. A distinction was made of Tan- 

 cienne terre and la nounelle terre, to which Rouelle 

 added a travaille intermediaire. Rouelle died in 

 1770, having been known by lectures, not by books. 

 Lehman, in 1756, claims for himself the credit of 

 being the first to observe and describe correctly the 

 structure of stratified countries; being ignorant, 

 probably, of the labours of Strachey in England. 

 He divided mountains into three classes 8 ; primi- 

 tive, which were formed with the world; those 

 which resulted from a partial destruction of the 

 primitive rocks ; and a third class resulting from 

 local or universal deluges. In 1759, also, Arduine 9 , 

 in his Memoirs on the mountains of Padua, Vi- 

 cenza, and Verona, deduced, from original observa- 

 tions, the distinction of rocks into primary, second- 

 ary and tertiary. 



The relations of position and fossils were, from 

 this period, inseparably connected with opinions 

 concerning succession in time. Odoardi remarked 10 , 

 that the strata of the Subapennine hills are uncon- 

 formable to those of the Apennine, (as Strachey had 

 observed, that the strata above the coal were uncon- 

 formable to the coal 11 ;) and his work contained a 



7 Encycl. Method. Geogr. Phys. torn. i. p. 416, quoted by 

 Fitton as above, p. 159. 



8 Lyell, i. 70. " Ib.72. 10 Ib-74- ll Fitton, p. 157- 



