THE ISLAND OF PORTO RICO 151 



Mountain series) and of the Virgin Islands, of which they 

 are probably an extension. 



It is probable that the rocks of the littoral are composed 

 in part of elevated coral reef, or seborucco, so common on 

 the other Antillean lands, but this has not been positively 

 determined. Great living reefs abound on the eastern sub- 

 merged platform along the south coast of the island, about 

 four miles offshore. 



According to Cleve, gold is found in loose pieces in the 

 rivers of Sierra Luquillo and Corazal, and mercury in the 

 Rio Grande. Gold was formerly mined by the early Span- 

 ish settlers, being found in placer deposits. Its quantity or 

 occurrence cannot be definitely stated at present. Molyb- 

 dena. magnetic pyrite, manganite, limonite, chrysocolla, 

 epidote, and garnet are the minor minerals found. Specu- 

 lar iron is reported in several places, notably on the Rio 

 Cuyul. Magnetic iron ore is also reported from Gurabo 

 and Ciales. Large, fine crystals of quartz are found in the 

 Rio Prieto ; agate of good quality at Kaja de Muestos, and 

 malachite at Rio Blanco. Don Pedro Resano in San Juan 

 has a very fine collection of the minerals of the island, the 

 specimens of which would indicate that a thorough geologi- 

 cal survey of the island might be profitable. 



Among the natural features of interest in the island are 

 the cave of Aguas-Buenas, in the village of the same name ; 

 the grand cave of Pajita Inlares ; the cave of Muertos in 

 Utuado; the cascade of Santa Alalia in Bayamon; and the 

 salines of the Cacique in Guanica. There are also many 

 thermal and mineral waters, such as the warm springs of 

 Coamo, Quintana, and others. 



In a mountain near the center of the village of Harmi- 

 gueros is the shrine of Montserrat, which was formerly 

 much visited by the inhabitants of the island, and many 

 from St. Thomas, Santa Cruz, Dominica, Guadeloupe, 

 Curacao, and Martinique. 

 \ Travelers claim that the climate of Porto Rico, although 

 warm, is more agreeable and healthful than that of any of 



