Jennings: Contribution to Botany of Isle of Pines. 27 



distance to the west of these mountains are the Casas Mountains, 

 slightly lower, but very similar in their general features. On the 

 northeastern coast is a still lower ridge (Bibijagua) of the same char- 

 acter as the other two. In the southwest, the Cafiada Mountains 

 rise to about one thousand feet (985 feet, Jennings; 1015 feet, 

 Britton), being composed of an impure quartzose mica-schist, with 

 some sandstone, and they have generally gentle slopes. 



The mountains and hills in the south-central and southeastern 

 parts of the island were not explored by me, but according to Britton, 

 /. c, they are partly limestone and partly sandstone and schist. 



The plains of the northern part of the island, from which rise the 

 hills and mountains just mentioned, are gently undulating, reaching 

 an elevation of about two hundred feet above the sea in the central 

 portion whence the drainage systems radiate towards the sea with 

 broad, gently sloping valleys. This plain is mainh' of subaerial 

 erosion, but around the bases of the northern mountains there is a 

 fine series of wave-cut cliffs at about fifty or sLxty feet above the 

 present sea-level. The outer margins of the plain mostly slope gently 

 into the sea and marginal coastal deposits are of considerable extent. 



There appears to have been in geologically recent times an eleva- 

 tion sufficient to enable the streams to cut down steep channels, at 

 least in their lower courses, and subsequent depression has converted 

 the lower parts of the rivers into deep inlets which are subject to tide- 

 water for several miles above their outlets. 



The soil of the plain in the northern part of the island consists 

 mainly of a yellowish-red or brownish-red (iron-stained) gravelly 

 clay, known as the "Mai Pais" gravel. This soil is evidently residual 

 and has been derived by subaerial erosion from underlying marbles 

 and schists. In depressions, however, and especially on the low plain 

 below the level of the ancient sea-cliffs, the soil is more largely a 

 yellowish or grayish sandy loam, while towards Los Indios in the 

 western part of the island the soil becomes chiefly sand, or sometimes 

 a pure white, angular, quartz gravel, with more or less iron ore (li- 

 monite). 



The part of the island south of the swamps consists of a rather 

 narrow area convex to the south and extending out to the west and 

 northwest in a long curve. This component of the island, known 

 locally as the "South Coast," is essentially a low plain of coralline 

 (or partly aeolian) limestone, rising somewhat to the south, where it 



