INTRODUCTION. 3 



stimulus to exertion, producing a larger accumulation of facts, and 

 a closer investigation of existing appearances, they wijl forward, 

 rather than retard, the progress of real knowledge; and, though they 

 occasion a few partial aberrations, they will ultimately subserve the 

 interests of science. 



Within these few years, the collection of geological facts has 

 been rapidly accumulating. Still, if we may judge from the jarring- 

 opinions held on the subject, we have not obtained sufficient data, for 

 establishing a general theory of the earth ; in other words, we cannot 

 satisfactorily explain the natural causes, employed by the Creator 

 to bring our globe into its present state ; which, as all agree, is widely 

 different from its original state. The chief thing to be done, there- 

 fore, in the present stage of the science, is to enrich it with ample 

 stores derived from actual observation; to collect information con- 

 cerning the characters, and relative positions, of the substances com- 

 posing the solid part of the globe; to specify their arrangement, 

 extent, and localities; and notice such hints as they may furnish for 

 elucidating the history of our planet. Every addition to these stores, 

 will serve to enlarge and consolidate the basis, on which a true 

 theory of the earth, if such can be found, must necessarily rest. 



It mvist be remembered, however, that here, as in other depart- 

 ments of science, there are boundaries which Ave cannot pass ; and 

 when om' researches shall have been pushed to their utmost limit, it 

 will still be found, that what we know, bears but a small proportion 

 to what we know not. As the astronomer, in exploring the celestiai 

 regions, is lost in immeasurable heights, so the geologist,, conducting 

 his pursuits in an opposite direction, is soon lost in unfathomable 

 depths. After examining every accessible portion of the globe, and 

 penetrating into the bowels of the earth as far as is practicable by 

 human labour, and collecting all the information within our reach, we- 

 shall still be totally ignorant of the interior of our planet, and can no 



