'32 THEORY OF THE EARTH. 



productions may be blended. Of this description 

 are the banks in the island of Guadeloupe, which, 

 along with human skeletons, present land and sea 

 shells mingled together. Of the same nature 

 also is the quarry described by Saussure, in the 

 neighbourhood of Messina, in which the sand- 

 stone is seen forming by the consolidation of the 

 sand thrown up by the sea. 



Litliopliytes. 



In the torrid zone, where lithophytes of many 

 species abound, and are propagated with great ra- 

 pidity, their strong trunks are interwoven and ac- 

 cumulated so as to form rocks and reefs ; and 

 rising even to the surface of the water, shut up the 

 entrance of harbours, and lay frightful snares for 

 navigators. The sea, throwing up sand and mud 

 upon the tops of these shoals, sometimes raises 

 their surface above its own level, and forms islands, 

 which are soon covered with a rich vegetation. 



Incrustation. 



It is also possible, that, in particular places, large 

 quantities of the animals inhabiting shells, leave 

 their stony coverings when they die, and that these, 

 cemented together by slime of greater or less con- 

 sistence, or by other cementing substances, form 

 extensive deposits or shell banks. But we have no 

 evidence that the sea can now incrust those shells 



