Notes on the Society's Work in 1897-1918. xxi. 



produce soils of extremely low and transient fertility from the point of 

 view of intensive cultivation. This action on basic rocks has been named 

 " lateritisation " and the more characteristic of the soils have been termed 

 " laterite" or "lateritic soils." No name has as yet been given to the some- 

 what similar but less complete action by which acidic rocks under tropical 

 conditions produce vast areas of almost barren white or greyish sand or 

 even of still more barren snow-white kaolin. 



A journey down the Surinam Railway to its terminus Dam on the 

 Sara Creek supplies excellent examples of such lateritic, sandy and 

 kaolinic areas and is at present the readiest way of ascertaining the 

 nature of many of the divides between river basins for 120 miles or so 

 from the Guiana coastlands. 



The action which converts igneous rocks into quartz-sand, kaolin, 

 bauxite and ironstone results in the formation of relatively sterile coun- 

 try Buch as that on the watersheds and divides between the great rivers 

 of this Colony. Great losses of capital have been incurred in other 

 countries by planting permanent economic products on lateritic or kaolinic 

 lands covered with high forest but which, although apparently very fertile 

 to the ordinary observer, are not of permanent fertility. The Imperial 

 Commissioner of Agriculture for the West Indies has specially asked 

 for a paper for the West Indian Bulletin on this subject. 



In 1910 I published a paper in the " Geological Magazine " on the 

 formation of the " earths commonly termed laterite'' in British Guiana 

 which dealt not only with these in situ on the basic rocks but also with 

 the kaolinic earths in situ on the acidic rocks. The accepted 

 authority on the marvellous fertility of the interior of this Colony after 

 reading my paper wrote to me under date of March 1st, 1911, as fol- 

 lows : — 



....'• Your paper on laterite as a product of weathering of 

 " the igneous rocks, British Guiana, is very interesting to ine. I 

 " came across plenty of laterite in Ceylon and very unpromising and 

 " intractable material it was for agricultural purposes. 



" It was possible in some districts, however, to turn it into 

 " account for growing tea. The iron in it seems to suit the tea 

 ■plant; but it was poison to coffee. . . . 



'• I have spoken a good deal lately about the possibilities of 

 '•development in British Guiana. My facts are nearly all derived 



" from the evidence you gave before the Royal Commission " 



In my 1897 address I carefully confined my statements as to low fer- 

 kility to " the non-occurrence of great tracts of land of exceptional fer- 

 tility " whilst I stated that " tracts [i.e., of land of exceptional fertility. 

 J.B.H.) of limi ed area may occur in valley land and river bottoms or on 

 lines of dykes of certain classes of intrusive rocks." 



The fact that residual soils formed in situ from igneous rocks in the 

 tropics are of low fertility, and that this is caused by leaching and elutria- 

 tion removing the constituents of the rocks which are essential for the 

 formation of fertile soils involves these substances accumulating else 



