124 Part IL. Chapter 1. 
also at the north-western end, which is steep too, while the southwestern 
point forms a low sand spit with shallow water for some distance from the 
shore. Along the coast line of the island occur alluvial formations often en- 
closing lagoons, which are gradually being filled with vegetable matter. 
b. Puerto Rico. 
Although this island nowhere attains the elevation of the mountains of _ 
Haiti and Jamaica, it is practically the eastern extension of the Antillean series 
of uplift. It rises from a submerged bank which borders it for a few miles 
and is continued across to the other islands. On the north slope, this bank 
descends almost precipitously to a depth of nearly 30,000 feet (9140 m) into 
what is known geographically as the Brownson Deep. The outline is nearly 
that of a parallelogram and the coast-line is almost perfectly straight, although 
there are a few headlands. The island landscape is a composite consisting of 
hills, fertile plains watered with numerous gently flowing streams. The 
mountains, generally low, rise to El Yunque in the Sierra Luquillo (3609 feet)?), 
the highest peak in the island. The extension of these mountains southward 
is known as Sierra de Cayey, while westward outlying ridges have various 
names. The southwestern end is a heaved-up area of mountains, hills, spurs, 
valleys, from which run down the many streams and rivers of the island, such 
as the Bayamon, Plata, Cibuco, Arecibo, Camuy which flow north, and the 
Culebrinas, Anasco, Guanagibo and Mayaguez, which flow west. The Port- 
ugues, Jacaguas, Coamo rivers flow west and the Humacao, Naguabo and 
Fajardo to the east. 
The geology of Puerto Rico is very little known. The hills according to 
Cleve a Swedish geologist are fragments of a very thick series of limestone 
strata which have been much denuded. The summits of the mountains are 
capped by the Antillean limestone formations. The presence of fossils shows 
that these limestones are identical in age with the Tertiary rocks, of the other 
Antilles. A core of older rocks, conglomerates, etc. are similar to the older 
rocks of Jamaica. The rocks of the littoral are probably coral and great reefs 
exist today on the east and south coasts of the island. 
c. Santo Domingo (Hispaniola). 
Santo Domingo excels Puerto Rico, Cuba and Jamaica in altitude, diversity 
of configuration, picturesque aspect and natural fertility °). It is continental in 
its topographic make-up, being the radiating center of the great Antillean 
uplif. The outline of Hispaniola is the most irregular of all the Greater 
Antilles, its periphery being nearly a thousand miles (1600 km), its length 
400 miles (644 km), and its breadth 160 miles (257 km). The great Gulf of 
ı) The maps indicate 1520 m near the west coast. (Drd.) 
2) HARSHBERGER, J. W.: An ecological Sketch of the Flora of Santo Domingo. Proceedings 
Academy Natural Sciences Philadelphia 1901: 554— 556. 
Ba a 
% 
“rg 
= 
Rn 
Fr.- 
H 
