28 Beautiful Shells, 



acid with the water; but this must be done very 

 cautiously, for if too strong it will remove all the 

 lustre from the surface of the shell subjected to 

 its influence. Sometimes the file, and a substance 

 called pumice-stone, has to be used, but these are 

 dangerous agents in inexperienced hands. The best 

 polish for the shell, after the skin is removed, is a 

 red earth called tripoli, applied on a piece of soft 

 leather. 



FOSSIL SHELLS. 



An eminent geologist, named Dr. Mantell, has 

 very beautifully and poetically termed rocks ^Hhe 

 Medals of Creation.-'^ As on coins and medals we 

 see stamped enduring records of great historical 

 events, so upon the rocks are written by the finger 

 of God a history of some of the mighty changes 

 which the earth has undergone, and fossil shells 

 are among the plainest and most easily read of 

 the characters or letters in which these truths are 

 written. As Dr. Harvey, in his " Sea-side Book,^^ 

 observes, " Shelly-coated mollusca have existed in 

 the waters of the sea, and in rivers, from a very 

 early period of the w^orld^s history, and have left 

 in its most stratified rocks and gravels abundance 

 of their shells preserved in a more perfect manner 



