Association of American Geologists and Naturalists. 247 



been suggested ; for, as regards the reality and continued opera- 

 tion of the causes upon which our induction is erected, it is quite 

 unimportant when or how the soHd materials of the earth were 

 formed ; because, commencing however or whenever they might, 

 they would be governed by the same chemical and physical laws 

 as now. 



AQUEOUS CAUSES. 



If the internal heat of the earth, with its permanent and effi- 

 cient causes, be admitted, we have solved the most difficult prob- 

 lems in geology ; for, immensely the greater part of our planet 

 is of igneous origin, and all that is due to water, if thrown like 

 a covering evenly around the globe, would form but a very thin 

 film — scarcely, in a section of a globe of four feet in diameter, 

 forming a visible line. The power of water is to dissolve, to 

 crystallize, to lacerate, to wear down, to transport and to deposit 

 the materials in new situations. 



In estimating the chemical effects of water, we must endow it 

 with all the solvent power which heat, under enormous pressure 

 under miles of ocean or of incumbent land, would give it ; and 

 then we must regard it not simply as water, but as a compound 

 fluid composed of all that water, in such circumstances, can dis- 

 solve ,• when perhaps red hot, a condition which it may well 

 attain, it might acquire new and remarkable energy — softening or 

 dissolving materials which might otherwise be unaff'ected by it. 

 These views would appear particularly important to any meta- 

 morphic theory of rocks, the changes of which it would seem 

 more reasonable to attribute to a conjoined operation of fire and 

 water than (as regards their crystallization) to impute them to 

 fire alone. 



Gentlemen, after having detained you so long, I am not dis- 

 posed to occupy any more of your time by discussing any pecu- 

 liar theories of the operation of water. Its effects, both mechan- 

 ical and chemical, are extensive and manifest to all. In the Wer- 

 nerian school, the solvent powers of water were exaggerated be- 

 yond all credibility ,• and at this day, no geologist would venture 

 to suggest that the mountains and the entire crust of the earth 

 have ever been dissolved in its waters. While in later times the 

 operations of fire have been, on substantial proof, (as on theory 

 alone they were formerly by Leibnitz,) prodigiously extended, 

 those of water have not been cancelled, although they have been 



