The relationship between key characteristics of a soil (e.g. organic carbon content, pH, cation-exchange capacity, percentage clay, total phosphorus, etc.) and the parent material from which it is derived, giving rise to fourteen soil types: alluvial, basaltic (see basalt), boulder clay, calcareous, chalk, clay, diorite, glacial till, granite, loess, sandy, schist, shale, and volcanic.

http://www.environmentdata.org/archive/vocabpref:19348 Lithological soil types.