Sarsen

Believed to have formed on the surface or in the near-surface of South England during warm phases of the Tertiary period, and broken down by frost action and mass movement.

Characterised as being extremely hard, finely grained, grey to brown sandstone. This stone has been used since prehistoric times, and was used extensively in the construction of Stonehenge.

Also known as greywethers or graywethers.

Sar"sen (?), n. [Etymol. uncertain; perhaps for saracen stone, i.e., a heathen or pagan stone or monument.]

One of the large sandstone blocks scattered over the English chalk downs; -- called also sarsen stone, and Druid stone.

© Webster 1913.