76 



GENERAL CONSIDERATIONS 



RESPECTING THE ORIGIN OF THE ANIMATED TRIBES 



Thus concludes the wondrous chapter of the earth's 

 history which is told by geology. It takes up our globe 

 at the period when its original incandescent state had near- 

 ly ceased ; conducts it through what we have every rea- 

 son to believe were vast or at least very considerable spa- 

 ces of time, in the course of which many superficial 

 changes took place, and vegetable and animal life was gra- 

 dually developed ; and drops just at the point when man 

 was apparently about to enter on the scene. The compi- 

 lation of such a history, from materials of so extraordina- 

 ry a character, and the powerful nature of the evidence 

 which these materials ^afford, are calculated to excite our 

 admiration, and the result must be allowed to exalt th& 

 dignity of science, as a product of man's industry and his 

 reason. 



If there is anything more than another impressed on ou*- 

 minds by the course of the geological history, it is, that 

 the same laws and conditions of nature now apparent to 

 us have existed throughout the whole time, though the 

 operation of some of these laws may now be less conspi- 

 cuous than in the early ages, from some of the conditions 

 having come to a settlement and a close. That seas have 

 flowed and ebbed, and winds disturbed their surfaces in 

 the time of the secondary rocks, we have proof on the yet 

 preserved surfaces of the sands which constituted margins 

 of the seas in those days. Even the fall of the wind-slat- 

 ed rain is evidenced on the same tablets. The washing 

 down of detached matter from elevated grounds, which 

 we see rivers constantly engaged in at the present time, 

 and which is daily shallowing the seas adjacent to their 

 mouths, onl^appear to have proceeded on a greater scale 

 in earlier epochs. The volcanic subterranean force, which 

 we see belching forth lavas on the sides of mountains, and 

 throwing up new elevations by land and sea, was only 

 more powerfully operative in distant ages. To turn to 

 organic nature, vegetation seems to have proceeded then 

 exactly as now. The very alternations of the seasons has 

 been re id in unmistakeable characters in sections of the 

 trees o1 those days, precisely as it might be read in a sec- 



