416 SIR CHARLES LYELL 



' Of these masses/ he might say, ' whether they consist of 

 loose incoherent sand, soft clay, or solid stone, none have 

 been formed in modern times. Every year some of them 

 are broken and shattered by earthquakes, or melted by 

 volcanic fire; and when they cool down slowly from a state 

 of fusion, they assume a new and more crystalline form, 

 no longer exhibiting that stratified disposition and those 

 curious impressions and fantastic markings, by which they 

 were previously characterised. This process cannot have 

 been carried on for an indefinite time, for in that case allj, 

 the stratified rocks would long ere this have been fused 

 and crystallised. It is therefore probable that the whole 

 planet once consisted of these mysterious and curiously 

 bedded formations at a time when the volcanic fire had 

 not yet been brought into activity. Since that period there 

 seems to have been a gradual development of heat; and 

 this augmentation we may expect to continue till the whole 

 globe shall be in a state of fluidity, or shall consist, in 

 those parts which are not melted, of volcanic and crystal- 

 line rocks.' 



Such might be the system of the Gnome at the very time 

 that the followers of Leibnitz, reasoning on what they saw 

 on the outer surface, might be teaching the opposite doc- 

 trine of gradual refrigeration, and averring that the earth 

 had begun its career as a fiery comet, and might be destined 

 hereafter to become a frozen mass. The tenets of the 

 schools of the nether and of the upper world would be 

 directly opposed to each other, for both would partake of 

 the prejudices inevitably resulting from the continual con- 

 templation of one class of phenomena to the exclusion of 

 another. Man observes the annual decomposition of 

 crystalline and igneous rocks, and may sometimes see 

 their conversion into stratified deposits; but he cannot 

 witness the reconversion of the sedimentary into the crys- 

 talline by subterranean heat. He is in the habit of regard- 

 ing all the sedimentary rocks as more recent than the un- 

 stratified, for the same reason that we may suppose him 

 to fall into the opposite error if he saw the origin of the 

 igneous class only. 



For more than two centuries the shelly strata of the 



. 



