L. Leigh Fermor — Laterites of French Guinea. 125 

 Table II.— Analyses of Laterites derived from Mica-schist and Alluvium. 



Notes. — Mineral compositions recalculated by me because Lacroix takes no 

 account of quartz and titania. Tbere must be a misprint in tbe first analysis. 



1 The value of n is shown in brackets in each case, n being 2 per kaolinite. 

 In analysis No. 16, 0-30 % H 2 has been added to bring n up to 3. 



2 In analyses 12 and 13 the hydrate is gibbsite, and not colloidal. 



3 In analyses 11, 12, and 13, some hematite is present, so that the amount of 

 Al 2 O3 • H 2 O must be less than that shown. 



of these rocks I have reinstated the quartz, as it is impossible other- 

 wise clearly to understand the case. No. 1-5 is then seen to contain 

 only 26 per cent of lateritic constituents, and the question of the 

 application of the term lateritoid does not arise. This rock is 

 clearly only a lateritic sandy alluvium. No. 14 shows 48 per cent 

 of lateritic constituents, and is therefore on the border-line between 

 a lateritic alluvium and a siliceous lateritoid, if the same limiting 

 percentages be adopted for the lateritoids as for the true laterites. 



