Orthent

Orthents are soils defined in USDA soil taxonomy as entisols that lack horizon development due to either steep slopes or parent materials that contain no permanent weatherable minerals (such as ironstone).

Typically, Orthents are exceedingly shallow soils. They are often referred to as skeletal soils or, in the United Nations FAO soil classification, as lithosols.

The basic requirement for recognition of an orthent is that any former soil has been either completely removed or so truncated that characteristics typical of all orders other than entisols are absent.