THE PLANT WORLD 35 



island of Cuba. From its southern shore the sea bottom rapidly descends 

 to the immense depths of the Caribbean Sea. Against it constantly beats 

 the equatorial current from the southeast as it passes through the Strait 

 of Yucatan into the Gulf of Mexico. That this stream is an important 

 agency in the dissemination of plants throughout the Antillean region 

 can not be doubted. It is here that Humboldt found the Palms and Pines 

 meeting, the former characteristic of the tropics, the latter of the north 

 temperate regions. 



The Isle of Pines is nearly bisected by a bay which penetrates nearly 

 one-half way across the island from its western side, and from the head 

 of this bay swampy land stretches almost continuously to the eastern 

 shore. 



The southern part is rocky but not mountainous, and according to re- 

 ports is heavily timbered with hard woods, such as mahogany. West In- 

 dian Cedar, Sabicu, Granadilla and other valuable timber trees. The 

 harborless sea shore and the almost impassable swamp have rendered these 

 forests so inaccessible as to prevent their exploitation. 



The northern and larger part of the island consists of a rolling table- 

 land in its highest parts scarcely more than 300 feet above tide. The 

 most conspicuous physiographic feature of this part of the island are 

 the mountains, which rise abruptly in isolated masses from this table- 

 land to a height of from 500 to 1600 feet. The principal ones are Sierra 

 Canada, Sierra Caballos, and Sierra Casas. The last two form parallel 

 chains several miles in length extending north and south in the northern 

 part of the island and end in abrupt headlands near the sea. The 

 mountains are peculiar in that they rise very abruptly from the plain, 

 their lower slopes being almost perpendicular masses of broken rock. 

 There are no foot-hills and the statement made by residents on the 

 island that the surface water on the plains drains toward the moun- 

 tains is apparently true. The rock is a metamorphosed limestone, in 

 many places affording beautiful marble. The marble of which Morro 

 Castle at Havana is built was quarried on this island. The mountains 

 have scarcely any soil and but little humus, yet support an abundant 

 vegetation over their entire surface. 



The soil of the plains is quite varied. It is porous but not sandy, 

 and is fertile. In the valleys it is dark and supports a dense vegetation. 

 The flora of the island taken as a whole is xerophytic in its tendency. 

 Upon the mountains this tendency manifests itself most strikingly. Not 

 only do plants grow upon the naked rocks but many plants such as 

 bromelias, orchids and aroids grow upon the trees and shrubs without 

 any direct connection with terra firma. Among the trees here were 

 species of Clusia, Ficus, and Cecropia, as well as others not identified. 

 On the rocks mingled with them were Plumerias, Bilbergias, Fourcroyas 



