PREFACE. 



THIS work attempts to hold a position between text- 

 books and books of light reading. The formal text- 

 book would not suit the class of readers addressed. The 

 style of light reading would have been unworthy of the 

 theme, and would not have supplied the substantial infor- 

 mation here intended. The writer has often felt that 

 graphic illustrations would have rendered portions of the 

 text more intelligible, and therefore, more entertaining ; 

 but these would have enhanced the cost of the book 

 beyond limits which for other reasons seemed desirable. 

 The method of treatment is simple. The reader be- 

 gins with the familiar objects at his very door. "His 

 observations are extended to the field, the lake, the tor- 

 rent, the valley, and the mountain. They widen over the 

 continent until all the striking phenomena of the surface 

 have been surveyed. Occasionally, trains of reasoning 

 suggested by the facts are followed out until the outlines 

 of geological theories emerge. The course of observation 

 and reasoning then penetrates beneath the surface. The 

 various formations and their most striking fossils are de- 

 scribed, first in descending order, to the oldest. We find 

 here indications of heat which stimulate speculation and 

 bring out the grounds of a nebular theory of world- 

 origin. From this starting point, the treatment now 

 handles the subject in historical order, weaving into a 



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