QO The Founders of Geology LECT. 



terrestrial crust. Not only had he met with no trace of any 

 igneous rock in the Alps, but the granite veins which he 

 found traversing a schist, and which he at once regarded as 

 throwing light on the origin of that rock, were believed by 

 him to be almost demonstrably due to infiltration, as the 

 granite itself had been formed from crystallization in the 

 waters of the ancient ocean. 1 



Even when he found the vertical conglomerate of 

 Valorsine, and recognized that it must have been originally 

 deposited horizontally, he refrained from hazarding a con- 

 jecture as to the reason of its position. "We are still 

 ignorant," he says, " by what cause these rocks have been 

 tilted. But it is already an important step, among the 

 prodigious quantity of vertical strata in the Alps, to have 

 found certain examples which we can be perfectly certain 

 were formed in a horizontal position." 2 



It is interesting, however, to notice that, among the 

 agenda which he inserted at the close of his last volume, 

 as the fruit of his long experience, he gives a chapter of 

 suggestions as to what should be looked for in regard to 

 organic remains among the rocks. Some of these suggestions 

 are full of sagacity, and show that, though he had not 

 followed them in his own researches, he recognized the 

 importance of the advice he was giving. One of his ad- 

 monitions was " to ascertain whether certain shells occur 

 in the older rocks but not in the later, and whether it is 

 possible by their means to fix the relative ages and eras of 

 appearance of the different species." Another recom- 

 mendation is " to compare exactly the fossil bones, shells, 



1 Vol. i. pp. 533 et seq. 

 2 Vol. ii. 690. 



