Sir H. Davy on the Formation of the Earth. 321 



vered with vegetables, fitted to bear a high temperature, such as palms and 

 various species of plants, similar to those which now exist in the hottest 

 parts of the world. And the submarine rocks, or shores of these new forma- 

 tions of land, became covered by aquatic vegetables, on which various species 

 of shell-fish and common fishes found their nourishment. The fluids of the 

 globe in cooling, deposited a large quantity of the materials they held in so- 

 lution, and these deposites agglutinating together the sand, the immense 

 masses of coral rocks, and some of the remains of the shells and fishes found 

 round the shores of the primitive lands, produced the first order of secondary 

 rocks. As the temperature of the globe became lower, species of the oviparous 

 reptiles were created to inhabit it ; — and the turtle, crocodile, and various 

 gigantic animals of the Sauri kind, seem to have haunted the bays and waters 

 of the primitive lands. But, in this state of things, there was no order of 

 events similar to the present ; — the crust of the globe was exceedingly slen- 

 der, and the source of fire a small distance from the surface. In consequence 

 of contraction in one part of the mass, cavities were opened, which caused 

 the entrance of water, and immense volcanic explosions took place, raisino- 

 one part of the surface, depressing another, producing mountains, and causino' 

 new and extensive depositions from the primitive ocean. Changes of this 

 kind must have been extremely frequent in the early epochas of nature ; and 

 the only living forms, of which the remains are found in the strata that are 

 the monuments of these changes, are those of plants, fishes, birds, and ovipa. 

 rous reptiles, which seem most fitted to exist in such a war of the elements. 

 When these revolutions became less frequent, and the globe became still 

 more cooled, and the inequalities of its temperature preserved by the moun- 

 tain chains, more perfect animals became its inhabitants, mauj' of which, such 

 as the mammoth, megalonix, megatherium, and gigantic hysena, are now ex- 

 tinct. At this period, the temperature of the ocean seems to have been not 

 much higher than it is at present, and the changes produced by occasional 

 eruptions of it have left no consolidated rocks. Yet, one of these eruptions 

 appears to have been of great extent, and some duration, and seems to have 

 been the cause of those immense quantities of water-worn stones, gravel, and 

 sand, which are usually called diluvian remains; and it is probable that this 

 effect was connected with the elevation of a new continent in the southern 

 hemisphere by volcanic fire. When tlic system of things became so permanent 

 that the tremendous revolutions depending upon the destruction of the equi- 

 librium between the heating and cooling agencies were no longer to be dread- 

 ed, the creation of man took place ; and, since that period, there has been little 

 alteration in the physical circumstances of the globe. Volcanoes sometimes 

 occasion the rise of new islands, portions of the old continents are constantly 

 washed by rivers into the sea, but these changes are too insignificant to af- 

 fect the destinies of man, or the nature of the physical circumstances of 

 things. On the hyjiothesis that I have adopted, however, it must be remem. 

 bered, that the present surface of the globe is merely a thin crust, sur- 

 rounding a nucleus of fluid ignited matter; and, consequently, we can hardly 

 be considered as actually safe from the danger of a catastrophe by fire." 



Onuphrio said, " From the view you have taken, I conclude that vou con- 

 sider volcanic eruptions as owing to the central fire ; indeed, their existence 

 JANUARY MARCH 1830. X 



