FOSSI LS. 



INTRODUCTORY. 



GEOLOGY is of all "hobbies" the one best calculated not only 

 to develop the physical powers, but also, if pursued with any 

 degree of earnestness, to train and extend the mental faculties. 

 To study geology properly, the rocks themselves must be visited 

 and carefully observed, their appearance noted, and the fossils, 

 if any, which they contain, collected. This necessitates many 

 a pleasant walk into the open country to quarries and cut- 

 tings, or rambles along the sea-shore to cliffs which may be 

 worth investigating, whilst botany, entomology, or any other 

 congenial pursuit, may be followed on the way ; for natural 

 science in its different branches has so many points of connec- 

 tion that it is impossible to study one of them without increas- 

 ing one's interest in, and knowledge of, all the others. Again, 

 in arranging, classifying, and studying at home the specimens 

 collected on these expeditions, many an hour may be usefully 

 spent ; habits of exactitude and neatness are acquired ; whilst 

 in endeavouring to draw correct conclusions as to the way in 

 which particular rocks were formed, and by what agencies 

 brought to their present position, the reasoning faculties are 

 exercised and developed. 



The existence of fossil shells and bones in various strata of the 

 earth's crust attracted attention at a very early date of the 

 world's history ; the Egyptian priests were aware of the exis- 

 tence of marine shells in the hills bounding the Nile valley, 

 and from this fact Herodotus drew the conclusion that the sea 

 formerly covered the spot. The bones of the larger mammalia 

 (rhinoceros, elephant, etc.), were, however, thought by the 

 ancients to be human, and hence arose the idea of a race of 

 giants having existed at some previous period of the earth's 



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