11 



The subsoil of this marsh is a white or yellow mass of loamy con- 

 sistency, and has the following composition : 



TABLE II 



(1) (2) (3) (4) 



Moisture, in fresh state 58.80% 55.73 42.21 66.38 



Moisture, air dry 2.69 1.88 2.62 3.72 



Insoluble residue U.33 0.27 1.88 0.26 



Carbon dioxide 41.78 39.41 38.19 37.0i 



Volatile matter not carbon I g 3g Q() 1Q4& t 3 



dioxide ) 



Oxide of iron and alumina 0.85 0.61 1.26 0.14 



Lime 51.22 4b. 41 45.50 44.14 



Magnesia 1.40 1.25 2.22 2.1-2 



Potash 0.07 U.07 0.06 0.0<o 



Phosphoiic acid 0.03 0.01 0.02 0.02 



Total nitrogen 0.19 0.50 0.66 0.48 



Humus 1.52 1.32 2.24 2.56 



Humus nitrogen 0.10 0.12 0.23 0.08 



% of humus. 6.49 9.19 10.25 7.22 



The samples were collected in the following places: 



No. 1 Cano de Tiburones, Colonia A, Pieza 3, 4 to 12 in. 



No. 2 San Vicente, Guarico, Subsoil. 



No. 3 Caho de Tiburones, Colonia A, Pieza 1, second foot. 



No. 4 Caho de Tiburones, Colonia A, Pieza 3, second foot. 



It appears from the analyses that this subsoil is a limestone, more 

 or less mixed with organic material. The moisture is quite high in 

 these samples in their fresh state, but they retain very little of it after 

 drying. The principal constituent is calcium carbonate with a small 

 amount of magnesium carbonate. The insoluble residue, the oxide of 

 iron and alumina, are insignificant, and the volatile matter is 

 practically all of an organic nature, with the exception of the carbon 

 dioxide in combination with lime and magnesia. Where the organic matter 

 rises to from 9 to 15%, the nitrogen is accordingly higher than in No. 1, 

 where the respective figures are only 3.38% of organic matter and .19% 

 of nitrogen. Potash and phosphoric acid are extremely low. It will 

 not be necessary to discuss at length the agricultural conditions of this 

 subsoil except in so far as it exerts an influence on the surface stratum, 

 for the simple reason that in most places the black layer is so thick that 

 the cane roots do not come in contact with the lime subsoil. The interest- 

 ing point in the composition of this subsoil is the fact that its calcareous 

 nature explains the high percentage of calcium carbonate in the black 

 soil, and the non-acidity of the same. If the subsoil consisted of material 

 devoid of calcium carbonate, the black soil would certainly be highly 

 acid, and any attempt at reclamation would be practically prohibitive or 



