J 



i 



Ch. XVII.] 



OF TEINIDAD. 



415 



A similar subsidence, at an earlier period, may probably 

 have given rise to the great pitch lake of Trinidad, the cavity 



having become gradually filled with asphalt. Every geologist 



is familiar with the odour emitted from what are called fetid 

 limestones when first broken. The Niagara limestone of the 

 Upper Silurian group in America is sometimes so impreg- 

 nated with bitumen, that this substance, when the stone is 

 burned for lime, flows from the kiln like tar."* 



* T. S. Hunt, ibid. p. 245. 





in 





ital 





