MANGANESE DEPOSITS OF SANTIAGO, CUBA/ 
By Arthur C. Spencer. 
The deposits of manganese which have thus far been worked in 
Cuba are all located in the vicinity of the city of Santiago, in the 
province of the same name, which is the easternmost on the island. 
The first ore, shipped in 1887, was a picked lot of 50 tons, and in spite 
of adverse conditions in regard to facilities for transportation, the 
output had increased by 1890 to 21,810 tons. From this time up to 
1898 the amount of ore annually mined was not so great, but various 
deposits were discovered and several mines were opened with varying 
success. As many as eight mines, which were worked previous to the 
revolution of 1895-1898, have been visited by the writer. 
The manganese ores of the Santiago region are mixtures in various 
proportions of the common oxides of manganese, probably including 
manganite, pyrolusite, braunite, and wad. The deposits occur in a 
region lying back of and parallel to the Sierra Maestra, between 
Guantanamo on the east and Manzanillo on the west, and in general 
coincident Avith the drainage basins of the Rios Cauto and Guan- 
tanamo. The geologic structure between the latitudes of the two 
cities named is that of a broad synclinal fold, with an east-Avest axis. 
From Cabo Cruz on the Avest to Guantanamo on the east the stratified 
rocks which compose the northern slopes of the Sierra Maestra dip at 
angles of from 10° to 20° toward the depressed area of the interior 
occupied by the Rios Cauto, Guaninicum, and Guantanamo, Avhile 
upon the north side of these drainage basins the strata rise as the 
mountains which occupy the country between them and the north 
coast are approached. The rocks exposed along the crest of the Sierra 
Maestra are coarse, well-stratified volcanic breccias, but upon the 
northern slope these soon jmss beneath strata showing an alternation 
of marine sediments and fine-grained volcanic tuffs, which are in turn 
covered by flows of basalt and still other f ragmental A r olcanic deposits. 
This essentially volcanic series grades into and finally gives place 
lo limestones and other purely marine sediments, as may be well 
observed along the neAv military road which crosses the high range of 
hills north of Santiago Bay, and at Cristo, Avhere the Moroto and 
"Report on a geological reeonnoissanee of Cuba, made under direction of Q-en. Leonard Wood, 
military governor; also Eng. and Min. Jour., August :.':», L903, pp. 62-69. 
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