Source: Atkinson, R. J. C. "Stonehenge". London, England: Westerham Press, 1987. page 11.
The outermost element of the site is the Avenue that runs straight down a gentle slope for 530m. The Avenue consists of twin banks about 12m apart with internal ditches, and it begins at the entrance to the earthwork enclosure. This is where the Heel Stone, a large upright unworked sarsen lies immediately adjacent.
Lying within the entrance is a sarsen stone, known as the Slaughter Stone. Arranged around the inner edge of the earthwork bank were originally four small uprights: the Station Stones, of which two are still visible.
Immediately adjacent to the bank is a ring of 56 pits, known as the Aubrey Holes, marked by circular concrete spots. The area between the inner edge of the bank and the outermost stone settings includes at least two further settings of pits: the Y and Z holes.
The “inner circle”
On the central area of the site there are the stone settings, the sophisticated arrangements that set Stonehenge apart from any other prehistoric monument in Europe. In their construction two types of stone were used: sarsen and bluestone. The sarsens used in the central settings are much large.
In its complete form
the outermost stone setting consisted of a circle of 30 upright
sarsens, of which 17 still stand, each weighing about 25 tons. The tops of
these uprights were linked by a continuous ring of horizontal sarsen
lintels. The edges are smoothed into a gentle curve which follows the line
of the entire circle. The Sarsen
Circle with its lintels is perhaps the most remarkable feature of
Stonehenge in terms of design, precision stonework, and engineering.
Newall, R. S. FSA. "Stonehenge". London: Her Majesty's
Stationery Office, and the Department of the Environment (Ancient
Monuments and Historic Buildings), 1959. page 6.