MINERAL PRODUCTIONS. 91 



preceding, seeming to indicate a common source and origin. 

 What is worthy of note in the waters of the mud eruptions," 

 adds the Doctor, " is the presence of iodine, a substance of high 

 medicinal powers. Containing it, they may be deserving of trial, 

 and may prove efficacious in all those ailments in the treatment 

 of which iodine has been found to be beneficial." 



Concerning the mineral productions of Trinidad, nothing 

 positive or definite can be said. It is contended that native mer- 

 cury has been found near Port of Spain, almost within its limits ; 

 the fact, however, is very doubtful, and has never been ascertained 

 by any intelligent inquirer. A small quantity of galena, or argen- 

 tiferous sulphuret of lead, was exhibited a few years ago as the 

 production of the hills to the north of the Santa Cruz valley. 

 The account is this : " Mr. A. Darmany, a cacao planter of the 

 valley, in the heat of the chase of a deer, came to a place in the 

 hills near the bed of a ravine, when his attention was attracted to 

 some substance of a brilliant aspect ; he picked up some of it, 

 which he brought to the Governor, Lord Harris, who had it 

 analysed. It was found to be galena, containing a small pro- 

 portion of silver. A handsome offer was made to the discoverer 

 if he could point out the locality whereon he had found the 

 precious ore ; he therefore went on an exploring excursion, but 

 failed to recognise the spot. Mr. Darmany died a few months 

 after of chronic dysentery, and nothing has been attempted since 

 to ascertain the truth of his report. Iron ore is very common, 

 and large pieces have been found in different parts, viz., at Las 

 Cuevas, and in the Quebrada de Hierro, or the Iron Ravine. 

 Specimens of chromate of iron have been exhibited as coming 

 from Point Galfat ; sulphate of copper is spoken of as existing at 

 Erin, and sulphur on the Pointe d'Or estate, near La Brea ; alum 

 is obtained at Huevos and Chacachacarreo. At St. Joseph, Arima, 

 and Guanape, a beautiful white clay is met with, which is used as 

 a whitewash for houses. 



Although sandstone is common, limestone is the only material 

 used for building purposes ; it is also extensively burned, near the 

 town, in the preparation of lime, which is regarded as being of 

 excellent quality ; brick and pottery earth exist in great abundance. 



Dr. Davy, whose opinions may be received as good authority 

 in such matters, has published the following considerations on the 

 geological structure and soils of Trinidad : 



