caliche

English Thesaurus

1. nitrate-bearing rock or gravel of the sodium nitrate deposits of Chile and Peru (noun.substance)

hypernym	:	rock, stone,
definition	:	material consisting of the aggregate of minerals like those making up the Earth's crust (noun.substance)

2. crust or layer of hard subsoil encrusted with calcium-carbonate occurring in arid or semiarid regions (noun.substance)

hypernym	:	dirt, soil,
definition	:	the part of the earth's surface consisting of humus and disintegrated rock (noun.substance)