TO THE USES OF MAN. 83 



plex disposition of the materials of the earth, which has re- 

 sulted from the operations of all these mighty conflicting 

 forces, if we consider the inconveniences that might have 

 attended other arrangements, more simple than those which 

 actually exist. Had the earth's surface presented only one 

 unvaried mass of granite or lava ; or, had its nucleus been 

 surrounded by entire concentric coverings of stratified rocks, 

 like the coats of an onion, a single stratum only would have 

 been accessible to its inhabitants ; and the varied intermix- 

 tures of limestone, clay, and sandstone, which, under the 

 actual disposition, are so advantageous to the fertility, 

 beauty, and habitability, of the globe, would have had no 

 place. 



Again, the inestimably precious treasures of mineral salt 

 and coal, and of metallic ores, confined as these latter chiefly 

 are, to the older series of formations, would, under the sup- 

 posed more simple arrangement of the strata, have been 

 wholly inaccessible ; and we should have been destitute of 

 all these essential elements of industry and civilization. Un- 

 der the existing disposition, all the various combinations of 

 strata with their valuable contents, whether produced by 

 the agency of subterranean fire, or by mechanical, or che- 

 mical deposition beneath the water, have been raised above 

 the sea, to form the mountains and the plains of the present 

 earth ; and have still farther been laid open to our reach, 

 by the exposure of each stratum, along the sides of val- 

 leys. 



With a view to human uses, the production of a soil fitted 

 for agriculture, and the general dispersion of metals, more 

 especially of that most important metal, iron, were almost 

 essential conditions of the earth's habitability by civilized 

 man. 



I would in this, as in all other cases, be unwilling to press 

 the theory of relation to the human race, so far as to con- 

 tend that all the great geological phenomena we have been 

 •considering were conducted solely and exclusively with a 



