Abstract
An appreciable departure from the principles of the different international classifications was necessary in the system adopted for the classification of soils derived from volcanic formations in Martinique and Guadeloupe and their representation on maps drawn on a scale of 1:20 000. The close relationship existing between the properties of soils as yet moderately evolved, derived from volcanic ash, and the mineralogical composition of their fine fractions justifies that this composition be accorded the importance it deserves. Nevertheless, our lack of knowledge concerning allophanic minerals, the different forms of halloysite, amorphous iron etc. and attendant consequences for soil properties, permits extrapolation of the results obtained in the West Indies to those in other countries only with due caution and when an in-depth study of the principal soil types warrants it.
