244 GEOLOGICAL RECONNAISSANCE OF THE DOMINICAN REPUBLIC. 



COAL. 



Lignite occurs at many places in the Republic. All outcrops seen during 

 the present investigation were small lenses and irregular masses in the 

 Tertiary sedimentary rocks. The age of the rock, where it was possible to 

 determine it, was Miocene, but the lack of suitable fossils made the deter- 

 mination of the age of some of the beds impossible. None of the outcrops 

 seen contained nearly enough lignite to be of any commercial value. 

 Most of the lenses are only a few inches thick and in many the lignite is 

 mixed with clay. Specimens of clean lignite ranging from material which 

 has the appearance of charcoal to hard, dense, black pieces with conchoidal 

 fracture and vitreous luster can be found, but all these specimens are very 

 small. No deposit of coal is known in the Republic, although some of the 

 lignite has been in places so much altered that specimens having the appear- 

 ance of coal can be obtained from it. The mode of formation of this coal 

 from the lignite is not definitely known. 



The lignite or coal does not appear to be mined or used as fuel anywhere 

 in the Republic. The lignitic streaks near Sanchez, Samana Peninsula, 

 are of no commercial value. 



AMBER. 



Pieces of amber have been found in stream gravels on the northwestern 

 border of the Cordillera Central, and there are rumors that some of it was 

 found in place. Very little has been done to work either the gravel or bed- 

 rock deposits for amber. In the vicinity of Tamboril, in the Cordillera 

 Septentrional, there are beds of sandy shale containing seams of lignite and 

 lumps of amber. The amber is of good quality, and the natives have for 

 many years shipped small quantities of it from this district, but most of 

 that shipped is obtained from the stream gravels. Exploratory work for 

 amber has been done by an American company, 1 which is reported to have 

 found natural gas in some of the holes. 



COMMON SALT. 



Common salt (sodium chloride) is obtained in the Dominican Republic 

 both by evaporation from sea water and by mining rock salt deposits. 

 Neither industry is large. The deposits of rock salt in Cerros de Sal north- 

 west of Barahona are described on pages 214-219. There is sufficient local 

 demand for the salt from these deposits to satisfy the present owners. 

 Larger and more efficient production could be made by installing modern 

 methods, but it is doubtful whether the returns would justify the outlay of 

 capital. 



GYPSUM. 



In the Cerros de Sal, associated with the salt deposits mentioned above, 

 there are thick deposits of gypsum. Plates of almost transparent selenite 

 are abundant, and masses of fine, snowy white alabaster occur in many 



'Sample, C. C, Engineering and Mining Jour., vol. 80, pp. 250-251, 1905. 



