71 
In conclusion, the object of this paper is to draw attention 
to the great masses of these bodies and the importance of 
alwa^^s noticing tlieir occurrence in geological formations, 
since it should be a very material help in regard to the cli- 
mate, and the conditions of the coasts and currents, besides 
being of great stratigraphical assistance; nor is it of less 
importance to note carefully the growth of recent ones, for 
only through a knowledge of the present can we interpret 
the past. 
