294 Geology. — On the Crust of the Earth, 



nite, reposing at high inclinations upon the flanks of the granite 

 mountains, with accompanying marks of violent dislocation, the 

 truth flashes upon us, and we perceive that these mountains 

 have once existed at lower levels, and that they have been 

 forced up through the superincumbent beds, by the expansive 

 power for ever struggling in the interior of the globe. It is thus 

 we become acquainted with the existence of a power capable 

 of the mightiest mechanical exertions. If earthquakes in our 

 own time rend the earth, dislocate its solid parts, and ingulph 

 portions of it in the chasms they produce, it may have been so 

 co-eval with the existence of the planet. If the volcano of 

 Skapta Jokul in Iceland, could, in 1783, pour out streams of lava, 

 sufficiently hot and voluminous, not only to melt down the an- 

 cient lavas, but to more than fill the gorge of a river two hun- 

 dred feet wide, and six hundred feet deep, damming up the 

 streams and inundating the whole country, so may it have been 

 in ancient geological times. If in 1822, the coast of Chili was 

 raised to the height of five feet, for one hundred miles, by a sin- 

 gle volcanic paroxysm, we can conceive of continents and moun- 

 tain chains being raised to their present elevation, by repeated 

 shocks in ancient times. In the account of the recent rising of 

 the volcano of Hotham Island in the Mediterranean sea, it will 

 be observed that the interval between the eruptions, was uni- 

 form between one hour and a quarter and one hour and a half, 

 and that the eruptions were followed by an evident increase in the 

 size of the island. The details of this rare spectacle are highly 

 valuable; they will be seized upon with great avidity by geolo- 

 gists, many of whom, we have no doubt, will consider the pheno- 

 menon as an epitome of those ancient parturitions of the ocean, 

 geology is s6 pregnant with. Finally, if at the present day, 

 springs peculiar to volcanic countries, deposit silex, bitumen, 

 Jime, and other substances, so it may always have been. And 

 indeed we have the physical assertions of these probabilities, in 

 the disturbed state of the lower stratified rocks, the extent of the 

 trap formations, the elevation of Italy, the Alps, and many other 

 regions, and the ancient beds of quarts, pitchstone, primary lime- 

 stone and oolites, which last approach so near to the modern 

 travertinos of Italy. Wherever volcanic waters are, there we 

 find calcareous and other mineral substances, and under circum - 

 stances encouraging the opinion, that they have at all times de- 



