1896.] Principles of Geology, and its Aim. 273 



thought in the 19th century. It broke down the belief in the 

 necessity of stupendous convulsions in past times. He adopted 

 and improved the views of Hutton, eliminating the baseless 

 theories mingled with them. He rendered great service in 

 elucidating North American geology, and published his travels 

 on this continent in 1845 and 1849. His " Geological Evi- 

 dences of the Antiquity of Man,'' published in 1863, startled 

 the public by its advocacy of Darwin's theory in the " Origin 



And so the science has advanced with rapid strides and is 

 solving the problems that are constantly arising in regard to 

 our planet, and upon its fixed data are based many of the 

 fundamental principles of philosophy. 



Having considered the history of the progress of geology, 

 let us now consider its aim and the fundamental principles 

 upon which the geologist bases his work. 



In the broadest sense, geology is the science whose province 

 is the planet upon which we live, its history from the begin- 

 ning to the present, including changes which have occurred 

 in regard to the condition at different periods, its several 

 physiographic features, its atmosphere, temperatures, and 

 aqueous bodies, and its life at different stages. In a nutshell, 

 the evolutionary progress of the earth. 



The narrow or commonly accepted view does not consider 

 the changes that have occurred, other than those that occurred 

 to the visible portion of the earth. Back of what is supposed 

 to be the earliest formation, it does not attempt to go. 



The latter view is sufficient for the ordinary geologist or for 

 the geologist who does not care to speculate on hypotheses 

 which refer to the origin of the earth ; but to the geologist 

 who is anxious to grapple with problems which require a 

 drawing upon the imagination for solution, this is not enough. 

 Chemists are not satisfied to study a drop of water, but they 

 are anxious to know its origin ; its composition is not suffi- 

 cient for them. Botanists and zoologists desire to know the 

 origin of plants and animals, not merely their structural and 

 physiological features. 



