Lithosphere 50–140 km thick (but beneath the mid-ocean ridges is no thicker than the crust), while continental lithosphere has a range in thickness from about 40 km to perhaps 280 km; the upper ~30 to ~50 km of typical continental lithosphere is crust. The mantle part of the lithosphere consists largely of peridotite. The crust is distinguished from the upper mantle by the change in chemical composition that takes place at the Moho discontinuity. Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle (peridotite) and is denser than continental lithosphere, for which the mantle is associated with crust made of
Common name or coinages; such names generally are difficult for laymen to learn, remember, and pronounce and so, in such books as field guides, biologists commonly publish lists of coined common names. Many examples of such common names simply are attempts to translate the Latinised name into English or some other vernacular. Such translation may be confusing in itself, or confusingly inaccurate, for example, "gratiosus" does not mean "gracile" and "gracilis" does not mean "graceful". The practice of coining common names has long been discouraged; de Candolle's "Laws of Botanical Nomenclature", 1868, the non-binding recommendations that form the basis of the modern