2 DEFINITION ,OF THE SCIENCE. 



DEFINITION OF THE SCIENCE. Geology may be defined 

 to be the inquiry into the natural history of the earth, extend- 

 ing through the animal, vegetable, and mineral kingdoms ; 

 and comprising, in its investigations, all time, past, present, 

 and to come. The present explains to us the past ; the past 

 and present reveal to us the future. The examination into 

 existing geological phenomena enables us to understand 

 those which have occurred in past periods of our earth's 

 history, to interpret nature by natural laws, and to appre- 

 ciate agencies and results which are obscure and remote, by 

 a comparison with such as are familiar and well known; 

 while the study, both of the past and present, empowers us 

 to deduce presages of the future, and to infer the nature of 

 those changes which may occur on the surface of our planet, 

 in future eras of its history. It may be described, in fine, 

 as an investigation of the structure of the earth, and 

 of the animals and vegetables which have existed on its 

 surface. 



Prom the above definition it will be perceived that geology 

 is by no means to be regarded as an isolated department of 

 knowledge, but rather as a union of all those sciences 

 which have for their object the study of nature, and the 

 perfections of her Divine Author. From the magnitude 

 and importance of the objects which it contemplates, geo- 

 logy may be considered in grandeur and extent as inferior 

 to none of the natural sciences ; whilst, in the varied and 

 attractive character of its investigations, it will be found 

 to surpass them all. So diversified is the sphere of its inqui- 

 ries, that it affords themes for contemplation fitted for every 

 order of mind ; and, while frequently, in the same object, it 

 calls attention to facts which the infant understanding may 

 comprehend, it offers problems which the loftiest intellect is 

 unable to solve. The shell imbedded in limestone, or the 

 vegetable converted into coal, the tyro may discover the one 

 to be a marine, the other a terrestrial production ; but the 

 process of the conversion of that shell into limestone, while 

 the animal matter is often replaced by flint, or the agency 

 by which the plant has been transmuted into a mineral 

 substance, while the woody structure is retained, involves 

 questions which the present state of our knowledge is 

 insufficient to determine. 



