The largest stone in Stonehenge’s inner circle, known as the Altar Stone, may have come from farther afield than its neighboring monoliths — possibly even from northern England or Scotland, according to a new study that questions a 100-year-old idea about the stone’s origins.
A century has passed since British geologist Herbert Henry Thomas published his seminal 1923 study on Stonehenge, in which he traced the origin of the “bluestones” that make up the monument’s inner circle to the Preseli Hills in western Wales. Among these bluestones — so called because they acquire a bluish tinge when wet or freshly broken and to distinguish them from the “sarsen” stones that make up the outer circle — Thomas included a 16-foot-long (4.9 meters) flat-lying, gray-green slab of stone known as the Altar Stone.