THE NATIONAL PARKS SYSTEM 259 



States Geological Survey very greatly increased botti 

 popular and scientific knowledge. 



Similarly, forty years of speculation and theo- 

 ries, widely commented on, preceded the recent solu- 

 tion, by Francois E. Matthes of the United States 

 Geological Survey, of the remarkable geologic his- 

 tory of the Yosemite Valley ; and the Grand Canyon, 

 Rocky Mountain, and Glacier regions were advanc- 

 ing popular education long before they became na- 

 tional parks. The writings of John Muir and other 

 naturalists, professional and amateur, attracted na- 

 tion-wide attention. Among investigators of the 

 United States Geological Survey, the writings of 

 Button and others in the seventies, and of Matthes, 

 Campbell, Alden, Lee and others in later years, not 

 to mention many connected with state and private 

 universities and institutions of research, had their 

 distinct influence toward popularizing the real mis- 

 sion of the National Parks. 



No doubt National Parks were used as class- 

 rooms by individual teachers and universities many 

 years ago. Probably the University of California 

 was the first, or among the first, to take advantage 

 of near-by opportunities. In 1915 Director Stephen 

 T. Mather and I found Dr. Lenertz, then of the 

 University of Minnesota, piloting a class in geology 

 on a study tramp through Glacier National Park, 

 the third or fourth of an annual series. Small 

 classes from the University of Utah visited the Zion 

 Canyon before it became a National Park. Doubt- 



