'lieularly down, petrified shells, and other marine sub- 

 stances, will be plainly discerned. In several parts of 

 Asia and Africa, travellers have observed th< j se shells in 

 great abundance. In the mountains of Castraven, they 

 quarry out a white stone, every part of which contains 

 petrified fishes, in great numbers, and of surprising diver- 

 sity, in such preservation, that their fins, scales, and all the 

 minutest distentions of their make, can be perfectly dis- 

 cerned. From all these instances we may conclude that 

 these fossils are very numerous. And the variety of 

 their kinds is astonishing. Most of the sea-shells which 

 are known, and many others to which we are entirely 

 strangers, are to be seen either 'in their natural state, or 

 in various degrees of petrifaction. But in the place of 

 some we have mere spar, or stone exactly expressing all 

 the lineaments of animals : for the shells dissolving by- 

 slow degrees, and the matter having exactly filled all the 

 cavities within, this matter retains the same ibnn which 

 the shells were of. 



The greatest depths of the sea ever yet sounded, 

 have been found to be about 3000 fathoms. The or- 

 dinary depths are about 150. Though these shells ave 

 to be found in almost all the plainer parts of the sur- 

 face of the earth, yet there are certain very large tracts 

 were such bodies are never found, viz. the mountains, 

 which seem to be the remains of the original strata of 

 the earth. It is true that there are many eminences, 

 which have been taken for mountains, where sea-shells 

 of every kind are found : but these are hillocs, com- 

 pared with the large mountains, which may -be traced in 

 immense chains, without almost any discontinuity, from 

 one continent to another ; and from continents to neigh- 

 bouring and opposite islands; insomuch that all these 

 chains, not only of the old, but likewise of the new- 

 world, seem connected one with another. In the Alps, 

 Apennine, and Pyreueans, no shells-, nor marine bodies 

 of any kind are to be found : neither in the large Gram- 

 pion mountains in Scotland. 



The same is observed of all the large mountains of 

 Africa, and of Asia, and in the huge chain of Cordil- 

 leras in .Peru. This kind of mountains (which indeed 



