THE PROGRESS OF GEOLOGY 415 



earth's history requires no ordinary share of discretion; for 

 we are precluded from collating the corresponding parts of 

 the system of things as it exists now, and as it existed at 

 former periods. If we were inhabitants of another element 

 if the great ocean were our domain, instead of the narrow 

 limits of the land, our difficulties would be considerably 

 lessened; while, on the other hand, there can be little doubt, 

 although the reader may, perhaps, smile at the bare sug- 

 gestion of such an idea, that an amphibious being, who 

 should possess our faculties, would still more easily arrive at 

 sound theoretical opinions in geology, since he might be- 

 hold, on the one hand, the decomposition of rocks in the 

 atmosphere, or the transportation of matter by running 

 water ; and, on the other, examine the deposition of sediment 

 in the sea, and the imbedding of animal and vegetable re- 

 mains in new strata. He might ascertain, by direct observa- 

 tion, the action of a mountain torrent, as well as of a marine 

 current; might compare the products of volcanos poured out 

 upon the land with those ejected beneath the waters; and 

 might mark, on the one hand, the growth of the forest, and, 

 on the other, that of the coral reef. Yet, even with these 

 advantages, he would be liable to fall into the greatest errors, 

 when endeavouring to reason on rocks of subterranean 

 origin. He would seek in vain, within the sphere of his 

 observation, for any direct analogy to the process of their 

 formation, and would therefore be in danger of attributing 

 them, wherever they are upraised to view, to some ' primeval 

 state of nature/ 



But if we may be allowed so far to indulge the imagina- 

 tion, as to suppose a being entirely confined to the nether 

 world some 'dusky melancholy sprite,' like Umbriel, who 

 could 'flit on sooty pinions to the central earth/ but who 

 was never permitted to ' sully the fair face of light/ and 

 emerge into the regions of water and of air; and if this 

 being should busy himself in investigating the structure of 

 the globe, he might frame theories the exact converse of 

 those usually adopted by human philosophers. He might 

 infer that the stratified rocks, containing shells and other 

 organic remains, were the oldest of created things, be- 

 longing to some original and nascent state of the planet 



