GEOLOGICAL CHANGE, AND TLME. 117 



which Smith established. At tirst it served merely to determine the 

 order of the stratified rocks of England. I>ut it soon proved to possess 

 ji worldwide value, for it was found to furnish the key to the struc- 

 ture of the whole stratitied crust of the earth. It showed that within 

 that crust lie the chronicles of a. long- history of i)Iant and animal life 

 upon this }>lanet, it sui)i)lied the means of arraugiiij^- the materials for 

 this history in true chronological sequence, and it thus oi)eued out a 

 mag'niticent vista through a vast series of ages, each marked l)y its 

 own distinctive types of organic life, which, in in-oportion to their an 

 tiqnity, dei)arted more and more from the aspect of the living world. 



Thns a liuudred years ago, by the brilliant theory of Hutton and tlie 

 fruitful generalization of Smith, tlie study of the earth rccei\"cd in our 

 country the impetus which has given birth to tlie modern science of 

 geology. 



To review the marvellous progress which this science has made dur- 

 ing the first century of its existence would recpiire not one, but many, 

 hours tor adeiiuate treatment. The march of discovery has advanced 

 along a multitude of different ]>aths, and tin? domains of nature which 

 have been included within the growing territories of human knowledge 

 have been many and ample. Nevertheless, there are certain depart- 

 ments of investigation to which we may protitably restrict our atten- 

 tion on the present occasion, and wherein we may see how the leading 

 }>rinciples that were proclaimed in this city a hundred years ago ha\ e 

 germinated and borne fruit all oxer the world. 



From the earliest times the natural features of the earth's surface 

 have arrested the attention of mankind. The rugged mountain, the 

 cleft ravine, the scarped cliff, the solitary bowlder, have stimulate«l 

 curiosity and prom]ited many a speculation as to their origin. The 

 shells embedded by millions in the solid rocks of hills far remo\ed frou! 

 the seas have still further pressed home these "obstinate questionings." 

 Hut for many long centuries the advance of inquiry into such matters 

 was arrested by the paramount intluence of orthodox theology. It was 

 not merely that the church opi)ose<l itself to the simple and obvious in- 

 terpretation of these natural |>henomena. So inq)licit had faith l)ecome 

 in the accepted views of tiie earth's age. and of the history of creation, 

 that even laymen of intellig<'n<'e and learning set themsehes unbidden 

 and in perfect good faitli to exi>lain away the difliculties which nature 

 so persistently raised up, and to reconcile her teachings with those of 

 the tlieologians. In the various theories thus originating, tlie amount 

 of knowledge of natural law usually stood in inverse ra,ti(t to the share 

 l)hiyed in them by an uncontrolled imagination. The speculations, for 

 exanq)le, of Ibirnet, Whiston, Whitehurst, and others in this country, 

 cau not be read now without a smile. Jn no sense were they scuentiflc 

 researches; tliey can only be looked upon as exercitations of learned 

 ignorance. Springing mainly out of a laudable desire to i)r(unote what 

 was belie\'ed to be the cause of true religion, they heli)ed to retard 



