Gregory — Progress in Interpretation of Land Forms. 105 



cultivate them. Steno (1631-1687) mildly suggested that 

 surface sculpturing, particularly on a small scale, is 

 largely the work of running water, and Guettard (1715- 

 1786), a truly great mind, grasped the fundamental prin- 

 ciples of denudation and successfully entombed his views 

 as well as his reputation in scores of books' and volumes 

 of cumbrous diffuse writing. 



At the beginning of the 19th century a sufficient body of 

 principles had been established to justify the recognition 

 of an earth science, geology, and the 195 volumes of the 

 Journal thus far published carry a large part of the 

 material which has won approval for the new science and 

 given prominence to American thought. From the pages 

 in the Journal, the progress of geology may be illustrated 

 by tracing the fluctuation in the development of fact and 

 theory as relates to valleys and glacial features, the sub- 

 jects to which this chapter is devoted. 



The Interpretation of Valleys. 

 The Pioneers. 



Desmarest (1725-1815) might be styled the father of 

 physiography. By concrete examples and sound induc- 

 tion he established (1774) the doctrine that the valleys of 

 central France are formed by the streams which occupy 

 them. He also made the first attempt to trace the his- 

 tory of a landscape through its successive stages on the 

 basis of known causes. His methods and reasoning are 

 practically identical with those of Dutton working in the 

 ancient lavas of New Mexico ; and Whitney's description 

 of the Table Mountains of California might well have 

 appeared in Desmarest 's memoirs. 2 The teachings of 

 Desmarest were strengthened and expanded by DeSaus- 

 sure (1740-1799), the sponsor for the term, "Geology," 

 (1779) who saw in the intimate relation of Alpine 

 streams and vallevs the evidence of erosion by running 

 water (1786). 



The work of these acknowledged leaders of geological 

 thought attracted singularly little attention on the Con- 

 tinent, and Lamarck's volume on denudation (Hydro- 

 geologie), which appeared in 1802, although an important 

 contribution, sank out of sight. But the seed of the 

 French school found fertile ground in Edinburgh, the 

 center of the geological world during the first quarter of 



