4 BULLETIN 354, U. S. DEPARTMENT OF AGRICULTURE. 



origin, an elevated area of coral limestone (former marginal marine 

 deposits) surrounding the mountainous portion, and the coastal plain. 



CENTRAL MOUNTAIN AREA. 



The central mountain area occupies by far the largest portion of the 

 island. Viewed from the sea it presents a rugged and serrated aspect; 

 numerous peaks and summits, with no definite crest line, rise from a 

 general mass, which has been cut by erosion into lateral ridges, sepa- 

 rated by deep, steep-sided gorges. The drainage divide is approxi- 

 mately parallel to the southern coast and about 10 or 15 miles distant 

 from it. The region thus has a long and relatively gentle inclination 

 toward the north coast, but falls off rather abruptly toward the south. 



The Sierra de Luquillo, 1 the most easterly of the three ranges making 

 up the central mountain mass, is surrounded by low coastal plains, and 

 is completely isolated, except for a low water-divide which crosses near 

 Las Piedras to the Sierra de Cayey. By thus completely dominating 

 the landscape it gains the appearance of being very high; and one of 

 its peaks, El Yunque (the anvil), has been credited with being the 

 highest eminence on the island. According to the most recent 

 determinations 2 this peak reaches an altitude of 1,062 meters (3,483 

 feet). The east peak has an elevation of 1,054 meters (3,457 feet) 

 and the west peak 1,020 meters (3,346 feet). 3 These higher peaks are 

 flanked by numerous lateral ridges which extend in every direction. 

 The valleys, known as "quebrados," are deep and gorgelike and are 

 separated one from another by very narrow, almost knife-edged 

 ridges, ''cuchillas." Falls, cascades, and rapids are conspicuous 

 features of the drainage system here. This range supports the only 

 large tract of virgin forest growth on the island. 



The remaining mountain mass forms an uninterrupted expanse of 

 broken uplands. The main crest line extends from Humacao on the east 

 through Aibonito and Adjuntas to within a short distance of Maya- 

 guez on the west coast. The portion east of Aibonito is known as the 

 " Sierra de Cayey;" that to the west, the " Cordillera Central." This 

 region has an average elevation of about 2,500 feet, above which the 

 higher peaks project irregularly, a few to an elevation of more than 

 3,500 feet. The thirteen highest peaks on the island are in the "Cor- 

 dillera Central." The highest of these (not named on the Coast and 

 Geodetic Survey chart) situated about due south of Jayuya, has an 



1 Herrera (see Bibliography) describes the Luquillo as follows: "Ten leagues East-South-East from the 

 City of Puerto Rico is a very high and great Mountain, with three Breaks on it, call'd del Luquillo, or of 

 the little Madman, on Account of a revolted Indian [that withdrew to it. The highest Point of it is 

 call'd Furzidi, a Name given by the Blacks, signifying a place always clouded, and the third is call'd of the 

 Holy Ghost." 



2 U. S. Coast and Geodetic Survey Chart 920, issued July, 1910. 



s These two together appear to be given the name " El Cacique " (The Indian Chief) by Gifford. He also 

 names the round. mountain to the west "El Toro" (The Bull), and the mountain next to it on the south 

 "ElCarnero" (The Sheep). 



