Masterpieces of Science 



untrained understanding, the contour of land 

 and of sea-floor, the aspect of shores, the condi- 

 tions of soil, etc. Under the head of Rivers and 

 Valleys we propose to consider one portion of 

 this simple but ample division of geologic 

 science. 



If the reader wishes to begin a series of studies 

 of an unprofessional character which will lead 

 him to some of the most important fields of 

 knowledge which the earth's science can open to 

 him, he cannot do better than find his way to his 

 subject through a river-valley. There are many 

 advantages offered to him in beginning his in- 

 quiries in this pleasant way. In the first place, 

 the outward aspect of the phenomena with 

 which he has to deal is already familiar to him. 

 We can all recall to mind some of these troughs 

 of the earth through which flows a stream, be it 

 mountain-torrent, brook, or river. The steep 

 or gentle slopes of the valley toward the agent 

 which has constructed it, the flowing water, as 

 well as many of the important actions of the 

 stream in its times of flood or in its cataracts, 

 are also familiar. In fact, there is not a feature 

 or a phenomenon visible in the valley which has 

 not a proper name, indicating that it is a matter 

 of common and easy observation. Whoever 

 will follow an ordinary stream from its source to 

 the sea in such a journey as he may make in a 

 few days' travelling, and will avail himself of its 

 teachings, with the aid of the simplest under- 

 standings derived from a knowledge of physical 

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