Xll INTRODUCTION. 



" Emersere fretis monies, orbisque per undas 

 Exiliit, vasto clausus tamen undique ponto." 



Such theories appear to have been first propounded by 

 Straton, the successor of Theophrastus in his school ; 

 and they were improved by Herodotus, and still more by 

 Strabo, who gave numerous instances of the changes of 

 sea and land. But it is not a mere theory, that what 

 has been will be ; and our own Shakespeare has pro- 

 phetically illustrated tfiis idea in one of his exquisite 

 sonnets : 



" When I hare seen the hungry ocean gain 

 Advantage on the kingdom of the shore, 

 And the firm soil win of the wat'ry main, 

 Increasing store with loss, and loss with store ; 

 When I have seen such interchange of state, 

 Or state itself confounded to decay ; 

 Ruin hath taught me thus to ruminate 

 That time will come " 



Sea and land are in some respects convertible terms ; 

 and the epithet of " earth-embracing/' given to the 

 former, conveys only an indistinct notion of their close 

 and inseparable union. One cannot exist without the 

 other. They contain many of the same ingredients. But 

 the sea is the main depository of all soluble matter; 

 and the greater number and bulk* of marine testacea, 

 compared with those which inhabit the land, may be 

 thus accounted for. The quantity of calcareous matter 

 from which the continual and immense construction of 

 shells is derived, appears to be infinitesimally small. 

 Liebig has calculated that sea- water contains only t a * 4 

 of its weight of carbonate of lime, this being the princi- 

 pal ingredient of molluscous shells. How little do we 

 appreciate the action and effect of elements which are 



* I have seen a specimen of Tridacna gigas, from Amboyna, said to 

 weigh 3 cwt. 3 qrs. 



