SEDIMENTARY AND METAMORPHIC ROCKS 83 
is bringing from within the earth much more material 
than it could if its temperature were lower; but all 
water in the earth acts as a solvent, although under 
different conditions there is a variation in the amount 
and kind of material dissolved. 
Fig. 33. 
Calcareous rock deposited by hot springs in Yellowstone Park. 
Deposit from Warm Water. Under favorable circum- 
stances, some or all of this load of dissolved material 
may be deposited. For instance, when water reaches 
the surface in the form of a hot spring, as it does so 
commonly in the Yellowstone Park, and in many other 
parts of the earth, it bears with it some minerals in 
