SIR CHARLES LYELL 225 



identity of the ancient and present system of terrestrial changes, he 

 will regard every fact collected respecting the causes in diurnal action 

 as affording him a key to the interpretation of some mystery in the 

 past. Events which have oqcurred at the most distant periods in the 

 animate and inanimate world will be acknowledged to throw light on 

 each other, and the deficiency of our information respecting some 

 of the most obscure parts of the present creation will be removed. 

 For as, by studying the external configuration of the existing land 

 and its inhabitants, we may restore in imagination the appearance of 

 the ancient continents which have passed away, so may we obtain from 

 the deposits of ancient seas and lakes an insight into the nature of 

 the subaqueous processes now in operation, and of many forms of 

 organic life which, though now existing, are veiled from sight. 

 Rocks, also, produced by subterranean fire in former ages, at great 

 depths in the bowels of the earth, present us, when upraised by gradual 

 movements, and exposed to the light of heaven, with an image of those 

 changes which the deep-seated volcano may now occasion in the 

 nether regions. Thus, although we are mere sojourners on the sur- 

 face of the planet, chained to a mere point in space, enduring but 

 for a moment of time, the human mind is not only enabled to number 

 worlds beyond the unassisted ken of mortal eye, but to trace the 

 events of indefinite ages before the creation of our race, and is not 

 even withheld from penetrating into the dark secrets of the ocean, 

 or the interior of the solid globe ; free, like the spirit which the poet 

 described as animating the universe, 



— ire per omnes 

 Terrasque, tractusque maris, coelumqiie profundum. 



