182 FRAGMENTS OF SCIENCE 



hardly necessary to inform you tliat since his time the do- 

 main of the naturalist has been immensely extended — the 

 whole science of geology, with its astounding revelations 

 regarding the life of the ancient earth, having been 

 created. The rigidity of old conceptions has been re- 

 laxed, the public mind being rendered gradually toler- 

 ant of the idea that not for six thousand, nor for sixty 

 thousand, nor for six thousand thousand, but for . eons 

 embracing untold millions of years, this earth has been 

 the theatre of life and death. The riddle of the rocks 

 has been read by the geologist and paleontologist, from 

 sub-cambrian depths to the deposits thickening over the 

 sea-bottoms of to-day. And upon the leaves of that stone 

 book are, as you know, stamped the characters, plainer 

 and surer than those formed by the ink of history, which 

 carry the mind back into abysses of past time, compared 

 with which the periods which satisfied Bishop Butler 

 cease to have a visual angle. 



The lode of discovery once struck, those petrified forms 

 in which life was at one time active, increased to multi- 

 tudes and demanded classification. They were grouped in 

 genera, species, and varieties, according to the degree of 

 similarity subsisting between them. Thus confusion was 

 avoided, each object being found in the pigeon-hole ap- 

 propriated to it and to its fellows of similar morpholog- 

 ical or physiological character. The general fact soon be- 

 came evident that none but the simplest forms of life lie 

 lowest down; that, as we climb higher among the super- 

 imposed strata, more perfect forms appear. The change, 

 however, from form to form was not continuous, but by 

 steps — some small, some great. *'A section," says Mr. 

 Huxley, "a hundred feet thick will exhibit at different 



