12 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. 



mountains, which indeed alone desen^e that name, are chiefly composed of vitri- 

 fiable matter; and if they are sometimes found to contain sea-shells, it is never 

 at great depths, nor in their original metallic or stony strata; though such bodies 

 are found in great abundance at the foot of mountains, and in the adjacent 

 valleys, in which there are many eminences in some parts continued in small 

 chains, though but of small extent, which contain marble, sea-shells, chalk, 

 and other calcinable matter, but never any veins of metal, though we frequently 

 find in them pyrites, ochre, vitriols, and other minerals, which have been 

 washed down from veins of iron and other metals, with which the higher moun- 

 tains abound, and have afterwards been deposited in the calcareous strata of the 

 valleys. 



Bufibn pretends, that all mountains have been formed by sea-currents; and a 

 little afterwards tells us, that all sea-currents are occasioned by sea-mountains. 

 Is it not natural here to ask, which of these two causes pre-existed? can such 

 reasoning as this, a circulus viciosus of the grossest kind, ever tend to improve 

 our knowledge, or give us just views of the works of the Creator? The learned 

 academician founds his opinion of all mountains having been formed by sea-cur- 

 rents, principally on two observations. The first is, that they are made up of 

 strata composed of sea-shells, and petrified marine bodies of different kinds ; the 

 2d, that in chains of mountains the prominent angLs always correspond with 

 the depressed ones on the opposite side of the valley, in the same serpentine way 

 as we observe in rivers, the banks of which are alternately hollowed and promi- 

 nent, according to the different resistance they give to the current of the water. 

 This observation was first made by Bourguet, and must be owned to be curious 

 and interesting. Buffon is of opinion, that these two essential observations put 

 together, form an invincible argument in proof of his theory, and such as could 

 scarcely have been expected in so seemingly obscure a point. As to the first ob- 

 servation, that all mountains are made up of strata composed of marine bodies, 

 it is so far from being true, that no mountains, properly so called, contain such 

 bodies; and as to the 2d, of the correspondence of the opposite angles of moun- 

 tainous tracts, it does not at all prove, as he would have it, that sea-currents 

 have formed these mountains, but only that there have been formerly such cur- 

 rents running between them, which currents have given them that form we now 

 observe them to have. To assert, that because currents of water have given 

 them that figure, therefore they have produced them, is as ridiculous, as if one 

 should say, that a river had reared its own banks, merely because it had given 

 them a serpentine form. 



BufFon. who pretends that the earth was at first entirely covered with water, 

 which afterwards dug channels for itself, and thus separated the sea from the 

 land; and the author of Telliamed, who endeavours to prove that this water goes 



