546 



KIRK BRYAN 



in a pocket in the underlying rock (Fig. 13 a). The overlying 

 material, which is usually unconsolidated and generally of rela- 

 tively small volume, may be of different kinds, of which the most 

 common are residual soil, alluvium, till, and wind-blown sand. 

 This is the prevailing type of spring in the till-covered hills of New 

 England and in the soil-covered crystalline rocks of the Sierra 

 Nevada. Most small springs are grouped under this head. 



LEGEND 



Lava 



SediTDentaTy rock 



Fig. 12. — Map of a part of the Hopi Buttes, Arizona, showing distribution of 

 mesa springs with reference to lava and sedimentary rock. (From Gregory.) 



Pocket springs at the western border of Owens Valley, California, 

 are described by C. H. Lee^ as follows: 



The springs at the mouth of Sardine Canyon derive most of their supply 

 from the run-off of the drainage area, which sinks into porous gravel deposits 

 in the lower canyon. There is also contribution from accumulations of slide 

 material on the mountain face at the mouth of the canyon. The flow from 

 this group (three springs) varies from 3 to i| second-feet. 



' C. H. Lee, "An Intensive Study of the Water Resources of a Part of Owens 

 Valley, California," U.S. Geol. Survey, Water-Supply Paper 2g4 (191 2), p. 44 and 

 Plate XXV. 



