Dr. L. Leigh Fermor — What is Laterite ? 507 



Arachnida — Arane^e : ? Protolycosa sp. 



Xyphosura : Anthracomarti : 

 Bellinurus bellulus, Koenig. Anthracosiro woodwardi, Pocock. 



B. koenigianus, Woodward. ^ cf _ f r it S chii, Pocock. 



B. lonqicaudatus, Woodward. T „ , 



g sp _ IncertjE sedis : Cyclus sp. 



Prestwichia anthrax, Prestwich. 



sp. VEETEBEATA. 



P. rotundata, Woodward. Pisces 



P. birtwelli, Woodward. ElonychthiD2E : Elonychthys sp. 



EURYPTERIDiE : INCERT^ SEDIS : 



Eurypterus moyseyi Woodward. F Ua cf ; dmtat z m 



E. derbiensis, Woodward. ^ irenulata, Moysey. 



SCORPIONES: Post-abdominal segment. Palceoxyris prendeli, Lesquereux.. 



Pedipalpi : Geralinura britannica, P. helicteroides (Morris). 



Pocock. Vetacapsula johnsoni (Kidston). 



I would here desire to express my great obligation to Dr. Henry 

 Woodward for assisting me in determining the specimens mentioned ; 

 also to Miss Gr. M. Woodward for the care and trouble she has taken 

 in making drawings for the illustration of this paper. 



Y. — What is Laterite ? 



By L. Leigh Fermor, A.E.S.M., D.Sc, F.G.S., Geological Survey of India. 



{Continued from the October Number, p. 462.) 



Detrital Laterite or Lateritite. — Many of the so-called low-level 

 laterites and some of the high-level laterites consist of admixtures 

 of detritus from the various varieties of laterite already mentioned, 

 with quartz and argillaceous detritus from granites and gneisses, the 

 whole cemented together by the action of water on the lateritic 

 constituents of the mixture. For such rocks the name detrital laterite 

 is available, and could be used in all cases in which the reconstructed 

 rock contained, say, at least 40 per cent of lateritic constituents. 

 Theoretically, detrital laterites may contain, as an upper limit, 

 100 per cent of lateritic constituents, corresponding to the case of 

 a detrital rock composed entirely of fragments of a pure laterite, 

 without admixture of extraneous constituents. From the above it 

 will be seen that I would allow greater elasticity in using the term 

 laterite for the detrital forms than for those formed in situ (see next 

 paragraph), provided the adjective detrital be carefully prefixed ; for 

 this word seems to me to imply the great variability of composition 

 that must characterize these secondary laterites. But if it were 

 considered desirable to avoid the use of the word laterite altogether in 

 this connexion, the obvious term to use instead would seem to be 

 lateritite, implying a rock the individual constituents of which are pieces 

 of laterite. This term would be of great utility, and could be applied 

 to all detrital and reconstructed lateritic rocks. The word is put forward 

 here merely as a suggestion, but if geologists were to distinguish, 

 in writing, between laterite, lateritoid, and lateritite, great clarit) r 

 could be introduced into the literature of these substances. 



