SARSEN TRILITHONS.
Reading edition
5 piers in situ, 3 prostrate, 5 missing.
From this list of missing blue stones we may safely deduct two; two pieces of rock are known to be beneath the turf, and there may be others. The most satisfactory derivation of Sarsens or Sassens is from the Anglo-Saxon word for a rock or stone—ses, plural sesen or sesons. The Inner Circle of blue stones and Inner Horse-shoe are composed of the “Blue Stones,” igneous rocks.