Tor (rock formation)

A tor, which is also known by geomorphologists as either a castle koppie or kopje, is a large, free-standing rock outcrop that rises abruptly from the surrounding smooth and gentle slopes of a rounded hill summit or ridge crest. In the South West of England, the term is commonly also used for the hills themselves – particularly the high points of Dartmoor in Devon and Bodmin Moor in Cornwall.

The word tor (Cornish: tor, Old Welsh: twrr, Welsh: tŵr, Scottish Gaelic: tòrr), meaning hill, is notable for being one of the very few Celtic loanwords to be borrowed into vernacular English before the modern era – such borrowings are mainly words of a geographic or topographical nature. Another such word is (from Welsh craig "rock").

Tors are landforms created by the erosion and weathering of rock; most commonly granites, but also schists, dacites, dolerites, coarse sandstones and others. Tors are mostly less than 5 meters (16 ft) high. Many hypotheses have been proposed to explain their origin and this remains a topic of discussion among geologists and geomorphologists, and physical geographers. It is considered likely that tors were created by geomorphic processes that differed widely in type and duration according to regional and local differences in climate and rock types.

...
Wikipedia