RIVERS AND VALLEYS 

 PROFESSOR NATHANIEL SOUTHGATE SHALER 



[Professor Shaler, a native of Kentucky, occupies the 

 Chair of Geology in Harvard University. Among his writ- 

 ings are "A First Book of Geology," "The Story of Our 

 Continent," "The Interpretation of Nature," "Illustrations 

 of the Earth's Surface," "Domesticated Animals," "Sea 

 and Land," "Nature and Man in America," and "Aspects 

 of the Earth," (copyright, 1889, by Charles Scribner's Sons, 

 New York,) part of the fourth chapter of which last work 

 is here given! 



THE greater part of the facts with which geol- 

 ogists have to deal possess for the general public 

 a recondite character. They concern things 

 which are not within the limits of familiar ex- 

 perience. In treating of them, the science uses a 

 language of its own, an argot as special as that 

 of the anatomist or the metaphysician. There 

 is, however, one branch of the subject the matter 

 of which demands no special knowledge for its 

 understanding, viz. : the surface of the earth. At 

 first, geologists were little inclined to deal with 

 the part of their field which is visited by the sun. 

 Gradually, however, they have come to see that 

 this outer face of the earth is not only a kindlier 

 but a more legible part of the great stone book, 

 and they have made a division of their work 

 which they entitle Surface Geology. In this 

 division they include all that is evident to the 

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