PLATE 30 

 Winter earth cores made by Pocket Gophers. 



a. Cores on surface of nlea(lo^^■ three miles east of Chinquapin, May 20, 1919, as left 

 after departure of winter snow. 



h. Manner in which superimposed earth cores put up in snow during winter serve to 

 bury rocks and thus develop a surface layer of soil. (Photo taken in Lyell Caiiou, 

 July 21, 1915.) 



c. Fresh workings put up during an eight-inch fall of snow in Yosemite Valley. 

 (Photo taken ofter a thaw, November 11, 1915.) 



(I. Eain-beaten cores covering up pine needles and branches on slopes near Tuolumne 

 Meadows. (Photographed July 10, 1915.) 



See text, p. 139. 



[70(1; 



