40 CUBA AND PORTO BIOO 



feci in altitude. The Cerro del Oro, 3300 feel high, is an- 

 other conspicuous peak in the ridge, seen aboul half-way 

 between Santiago and Cape Cruz. LaGran Piedra, in this 

 range, near Santiago, is 5200 feet high. The summit of 

 this peak, from which it takes its name, is a gigantic block 

 of conglomerate, which see%is ready to topple down. East 

 of Santiago the range is called the Sierra del Cobre. From 

 base to summit these mountains are densely wooded, the 

 vegetation ranging from coarse cactaceous chaparral on 

 the lower and drier slopes to beautiful, almost indescriba- 

 ble, forests of tree-ferns in the higher and moister alti- 

 tudes. These mountains are composed of non-calcareous 

 conglomerates and shales of Mesozoic and Eocene age, 

 intruded by great masses of dark-colored, mid-Tertiary, 

 igneous rocks, the debris of which makes a clay and gravel 

 soil, one of the two contrasting types which constitute 

 the greatest wealth of the island, the whole incrusted on 

 the coastward side to a height of 2000 feet or more by 

 white limestones. The lower slopes are terraced after the 

 manner of all the east end of Cuba, as previously described. 

 The Sierra Maestra crest closely parallels the adjacent sea- 

 coast, toward which its slopes descend precipitously. In- 

 land, toward the north, the slope is gentler, the eroded 

 lateral ridges leading gradually down to the valley of the 

 Cauto, the deep east-and-west indentation of which nearly 

 separates these mountains from the region to the north. 



A second group of mountains is the Sierra de los Or- 

 ganos, found in the extreme western province of Pinar del 

 Rio, extending northeast and southwest between Mariel, 

 near Havana, and Cape San Antonio. This range consists 

 of lower ridges and of geologic formations different from 

 those of the Sierra Maestra. Its summits culminate in the 

 Pan de Gruajaibon, west of Havana, which has an altitude 

 of 2532 feet. Its rocks are composed of deformed sedi- 

 mentaries of supposed Paleozoic, Triassic, Jurassic, and 

 Tertiary age, the uplift of which may have been cumula- 

 tive, but culminated during the close of the last- mentioned 



