RUINATE LANDS. 17 



seen the steepest possible slopes cultivated to the highest degree in 

 coffee and tobacco; in fact, the most productive crops of this character 

 are grown upon declivities upon which the American farmer would not 

 risk limb and life. 



The soils of the coast-border region are of two major types: (1) The 

 soil of the limestone foothills; (2) the alluvial soil of the play a plains. 



The soils of the foothill region are the residua of the chalky lime- 

 stones and marls of the substructure, and are excessively calcareous, 

 very much resembling the chalky lime soils of northern Mexico and 

 the Eio Grande region of Texas. On the wet north side, where there 

 is more moisture, the limestones are more decayed and the regolith 

 is deeper, the resultant soils being a red residual calcareous clay 

 from which the excess of lime has largely been removed by solution, 

 although lumps of undecotnposed coral limestone remain. On the south 

 the regolith is shallow and the soils are correspondingly thin. Further- 

 more, they contain an excessive proportion of lime. In places, notably 

 near Guayanilla, these hill soils are less than a foot in depth, and are 

 underlaid by incrustations of the peculiar calcareous pan known in 

 Mexico as "tepetate." These chemical, physical, and climatic differ- 

 ences produce a more stunted arborescent growth than the red clays of 

 the mountain region. At least, the vegetation is dwarfed and largely 

 made up of different species. The limestone hills are mostly grazing 

 lands. The soils of the white limestone districts of the pepino hills 

 are of a different type from those of the hills of the coast-border 

 region. Those of the pepino hills are in general of a marly character, 

 whitish below and black in the exterior. Upon the hilltops they are 

 thin and unproductive, but where gathered into local valleys they are 

 deep and rich, and are considered among the most productive on the 

 island. 



The soil of the playa plain is purely alluvial, usually consisting of a 

 rich, red loam. These extensive alluvial deposits combine essentially 

 the qualities of the residual soils, both of the clay mountains and the 

 calcareous foothills, with the additional advantage of a more loamy 

 physical structure adapted for better drainage and root penetration 

 and general cultivation. In the northwest portion of the island, where 

 the alluvium is principally derived from the calcareous pepino hills, 

 the soils are blacker and more calcareous. These soils constitute the 

 sugar lands, and Porto Rico's sugar-producing capacity can be meas- 

 ured by their areal extent. 



RUINATE LANDS. 



Much of the soil of Porto Rico is now abandoned and in the condition 

 known throughout the English-speaking West Indies as "ruinate.' ; 

 This has resulted from long cultivation, from the failure to apply ferti- 

 lizers, and, in some cases, from erosion. Land of this character was 

 observed in many parts of the island. On the north coast, in the 

 22170— Bull. 25 2 



