L. Leigh Fermor — Laterites of French Guinea. 79 

 Diabases, and Pebxdotites. 



4 Lacroix regards all the Al 2 Os as present as gibbsite, presumably 

 assigning to the argile a lower state of hydration than n = 2. 



5 Picotite. 



6 Sample obtained by powdering twenty-five.pieces of red ore. 



