_Gravelly loams_ are from one-fourth to two-thirds coarse grained; the
remaining fine soil may be sandy loam, silt or clay loam. They are
adapted to various crops according to the character of the fine soil.
Some of them are best planted to fruit and forest.

_Stony Loam._--Like the gravelly loam the stony loams are one-fourth
to three-fourths sandy, silty or clay loam, the remainder being rock
fragments of larger size than the gravel. These fragments are
sometimes rough and irregular and sometimes rounded. The stones
interfere seriously with tillage, and naturally the soils are best
planted with forest or fruit.

_Clay Soils._--Clay soils are mixtures of sand, silt, clay and humus,
the clay existing in quite large quantities, there being a greater
preponderance of the clay characteristics than in the clay loams; they
are very heavy, sticky, and difficult to manage. Some clay soils are
not worth farming. Those that can be profitably tilled are adapted to
wheat, corn, hay and pasture.

_Adobe Soils._--These are peculiar soils of the dry West. They are
mixtures of clay, silt, some sand and large amounts of humus. Their
peculiar characteristic is that they are very sticky when wet and bake
very hard when dry and are, therefore, very difficult to manage,
though they are generally very productive when they are moist enough
to support crops.

_Swamp Muck_ is a dark brown or black swamp soil consisting of large
amounts of humus or decaying organic matter mixed with some fine sand
and clay. It is found in low wet places.