78 L. Leigh Fermor — Later ites of French Guinea. 



Table I. — Analyses of Laterites derived from Nepheline- syenites, 



Notes. — The mineral compositions have been recalculated by me, because Lacroix 

 takes no account of the insolubles or titania, and often omits to state the composition 

 of the argile. 



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



M Omitting a surplus of 2-08 % water above that required per n = 2 in the silicate. 

 It is equivalent to 37 H 2 O.if taken into the silicate. 



3 Lacroix terms this rock argile bauxitique, but describes the presence of gibbsite. 



