236 GEOLOGICAL RECONNAISSANCE OF THE DOMINICAN REPUBLIC. 



in the United States, even if situated at a locality convenient to a supply of 

 acid, could not be profitably worked unless it contained at least 1 per cent 

 of nickel and included at least a million tons. In a region such as the 

 Dominican Republic, with its transportation difficulties, the ore must be 

 much richer in order to be profitably extracted. The evidence at hand 

 gives but little encouragement to the hope that the nickel deposit at Sierra 

 Prieta can be profitably mined while nickel is at its present price. 



Further exploration of neighboring areas of the serpentine rock may 

 possibly disclose a richer deposit. Nickel in disseminated form is a usual 

 constituent of serpentine, and the deposit at Sierra Prieta is therefore not 

 unique. The disappointing results of prospecting there need not dis- 

 courage search in other parts of the Republic that are covered by extensive 

 tracts of serpentine. 



SAN CRISTOBAL MINING DISTRICT, PROVINCE OF SANTO DOMINGO. 



By Clyde P. Ross. 

 LOCATION AND ACCESS. 



The copper deposits in the old San Francisco concession, north of San 

 Cristobal, were examined by the writer during four days early in June, 1919. 

 The accompanying map (PI. XXIII), which is a reduction of a map made 

 by the engineer of the Blanton Syndicate, shows the area occupied by the 

 deposits. The office of the operators was at Naranja Dulce, on the west 

 side of Rio Nigua, about 13 kilometers north of the town of San Cristobal. 

 The principal workings on San Francisco Hill are directly across the river 

 from Naranja Dulce. Carts are said to have traveled the trail from San 

 Cristobal to the mines to carry ore when the mines were shipping — a journey 

 that would be possible only in the dry season, and much work would now 

 be necessary to put the trail in shape for the use of carts even then. In 

 the rainy season the trail is at times impassable. It would be difficult 

 but by no means impossible to build a wagon road from some point on the 

 Santo Domingo-San Cristobal Carretera to Naranja Dulce and Biicaro 

 Hill. 



In addition to the openings on Bucaro and San Francisco hills a number 

 of others are scattered over the district, but the only important ones are 

 those recently made by Dr. Jacob Harootian near the crest of the divide 

 between Rio Nigua and Rio Jaina, not far from the source of Arroyo 

 Platanito, at a locality called La Rama, which has been approximately 

 plotted on the map (PI. XXIII). It 'can be reached by a rather steep moun- 

 tain trail from Naranja Dulce. A trail or even a wagon road could prob- 

 ably be constructed from this prospect to Jaina or to some point on the 

 carretera between Jaina and San Cristobal, and thus shorten considerably 

 the distance to Santo Domingo City. 



