Rankers are

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

s developed over non-

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an a ...

material, usually rock. They are regarded in some

soil classification Soil classification deals with the systematic categorization of soils based on distinguishing characteristics as well as criteria that dictate choices in use. Overview Soil classification is a dynamic subject, from the structure of the system, ...

s as lithomorphic soils, a group which also includes

rendzina Rendzina (or ''rendsina'') is a soil type recognized in various soil classification systems, including those of Britain and Germany as well as some obsolete systems. They are humus-rich shallow soils that are usually formed from carbonate- or occ ...

s, similar soils over calcareous material. They are often called A/C soils, as the

topsoil Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Description Topsoil is composed of mineral particles and organic matte ...

A horizon A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. ...

is immediately over a C horizon (unaltered

parent material Parent material is the underlying geological material (generally bedrock or a superficial or drift deposit) in which soil horizons form. Soils typically inherit a great deal of structure and minerals from their parent material, and, as such, ar ...

).Soil Glossary
. InnVista.com. Accessed May 5, 2012.

References

Pedology Types of soil {{Soil-sci-stub