CLASSIFICATION OF SPRINGS 



533 



flow, not subject to annual fluctuations. They are usually warm 

 or hot, and many are highly mineralized. They appear to rise 

 along deep fractures extending far into the crust of the earth. The 

 fractures are similar to those in which were formed the veins now 

 found in mining operations. Doubtless the waters that deposited 

 veins in many places reached the surface as springs. 



Certain fissure springs lie along definite lines, and these lines 

 are known to be recent faults involving earth blocks of great depth. 



12 3 4 5 



Fig. 2. — Sketch map of Lassen Peak region, California 



Faulting appears to produce the fractures which allow these deep 

 waters to rise and carry the temperatures of the deeper crust to 

 the surface. Such springs may be called fault springs. The 

 thermal springs east of the Fish Springs Range, in Juab County, 

 Utah, are a classic example of springs of this type (Fig. 3). The 

 Fish Springs Range is the result of block faulting. The range has 

 a distinct tilt to the west and the fault runs along the eastern flank. 

 Very recent faulting is shown by a fresh fault scarp in the alluvium 



