INTRODUCTORY ESSAY. 



15 



* 



rested their labours in forming the external crust 

 of the greater part of Barbados^ is a lower eleva- 

 tion of the same primary rock, which appears as 

 mountains in some of the other islands. But if the 



V 



range of action of'the madreporae, &c. be limited 

 to twenty-five or thirty feet, in what manner has 

 the coralline crust been formed of so much greater 

 thickness in Barbados ? That it is of greater thick- 

 ness is quite certain; for the formation extends 

 uninterruptedly for many iniles, intersected in 

 every direction by deep ravines or gullies, the 

 precipitous walls of which are exposed to a much 

 greater depth than twenty-five or thirty feet. 



Whether 



een ele- 



vated, or that the waters have subsided, this fact 

 appears to me at variance, and indeed irrecon- 

 cileable, with the position laid down by M. M. Quoi 

 and Gaimard; for if the range of action of the 

 submarine zoophites be circumscribed, as stated 

 by these naturahsts and others, no supposed ele- 

 vation, no tilt or dislocation of the coralline mass, 

 can in any way account for the phenomena, which 

 in numberless places present themselves to obser- 

 vation in Barbados. 



I would next observe, that the argillaceous mine- 

 rals are constantly superimposed on the calcareous, 

 into which they pass abruptly. Also that the 

 argillaceous minerals are found only on the North- 

 Eastern portion of the island, in a deep hollow, 



v.^ 



