My own view was that the trilithons
had marched east under their own steam, strange headless beasts, the last of the giants.
How many trilithons
are standing at Stonehenge in Wiltshire?
These cultures, which erected the huge trilithons
that marked the lunar and the solar standstill positions at the horizon, must have been highly stratified, with specialized groups each assigned their own role in the project.
Recent radiocarbon dates from Stonehenge, though, show that the sequence of its three megalithic phases was: (1) on or before 2700 BCE, the first bluestone setting was erected; (2) the bluestones were removed from the Q and R Holes and the imposing sarsen lintelled circle and trilithons
were constructed around 2500 BCE; (3) finally, about 2250 BCE, the bluestones were restored as a circle and horseshoe inside the sarsens.
The word is actually derived from an early English word meaning 'hanging' in the sense 'suspended', as with 'hanging gardens', 'hangers' -- copses on the steep sides of Wiltshire's downs -- and the 'hanging' lintels across the uprights forming the trilithons
so uniquely characteristic of Stonehenge.
was a freestanding post and lintel structure, increasing in height from the open end of the horseshoe to the tallest one at the opposite end.