Soils and earths

1143. Soils may generally be distinguished from mere masses of earth by their friable texture and dark colour, and by the presence of some vegetable fibre or carbonaceous matter. In uncultivated grounds, soils occupy only a few inches in depth on the surface, unless in crevices, where they have been washed in by rains ; and in cultivated soils their depth is generally the same as that to which the implements used in cultivation have penetrated.