274 ELEMENTARY GEOLOGY 
the rain water, which dissolves a little carbonate of 
lime, and soon afterward deposits some of it as 
cement. This action is well illustrated in the Ber- 
muda Islands (Figs. 65 and 155). 
Exc. 155. 
Coral sand in Bermuda, cemented to rock by rain-water action. 
Water is always moving through the rocks, and as 
it goes, doing some chemical work. One of its impor- 
tant actions is to dissolve here and deposit there, and 
thus cement the rock particles together. This action 
of solution and deposition becomes stronger if the 
water is warm or hot, for then chemical action is 
