200 



(7.) The Cretaceous rocks occupy wide expanses of surface about 

 the Central range and near Pointe-a-Pierre. They consist of sand- 

 stones at the top and clays, shales and sandy shales with small 

 limestone bands below ; small outcrops of hard marl also appear here 

 and there. The sandstones are very pure and siliceous giving light 

 barren soils upon which cacao could not be grown profitably. The 

 clays and shales on the other hand ought to provide excellent soil. 

 They are harder and more distinctly bedded than the Tertiary clays, 

 and as a general rule coarser in grain. Minute glistening flakes of 

 clastic mica point to the presence of alkalis probably in greater 

 quantity than in the Tertiary clays, while the presence of sandy 

 material will render the soil more porous. The presence of thin bands 

 of limestone and concretionary nodules of iron-carbonate indicate a 

 diversity of composition which should be beneficial, and the soil 

 formed by the disintegration of these rocks should contain nearly all 

 the essential characters of a good cacao soil. 



In the course of the geological survey very little of these clays 

 and shales has been seen planted in cacao, but considerable areas of 

 the highwoods near the Cunapo River and east of Tamana are formed 

 of these rocks, and as the ground becomes opened up by roads it will 

 probably be found that valuable cacao estates can be established in 

 such districts. 



(8.) Only small portions of the northern range have been tra- 

 versed and full information about the soils has not been collected. 



The soil and surface wash of the range varies considerably in 

 composition and character according to the strata exposed. As a rule 

 the soil is a red sandy clay containing fragments of undecomposed 

 rock. The quantity of mica and talcose minerals in the rocks ensures 

 a considerable proportion of alkalis and magnesia in the soil, while 

 in the neighbourhood of the limestone outcrops, a fair percentage of 

 lime should not be lacking. The ground is steep and hilly almost 

 invariably, and so should drain easily. 



Phosphatic and pen manures will probably have the greatest 

 effect in increasing the yield of cacao on such soils. 



The washed-down detritus of the range extends for some distance 

 to the southward of the line of hills, but the nature of the soil does 

 not vary greatly, though the more soluble constituents may be 

 expected to have been removed to a greater extent from the material 

 which has travelled farthest. 



It seems to be generally admitted that the yield of cacao can be 

 increased greatly by careful and judicious cultivation, but it is 

 evident that different methods and different manures must be 

 employed for different soils, if the best results are to be obtained. 

 These notes are submitted in the hope that they may be of use to 

 those interested in the cacao industry, as a guide in the forming of 

 new, or the treatment of old established, estates, in so far as the 

 development of the ground and the yield of cacao are determined by 

 geological conditions. 



[These notes were written at the end of Mr. Cunningham-Craig's first year's 

 work in Trinidad, and he considers them only a preliminary excursion into the 

 Jsubjec Much additional information lias since been collected. — Ei>.] 



