In the past Stonehenge has been a battleground on which archaeologists have fought with assumptions as their only weapons, but within recent years careful and systematic excava tion, if it has not furnished definite evidence as to the purpose and date of construction of the monument, has at least added considerably to our knowledge.
The Avenue, first described in 1723 by Stukeley, approaches Stonehenge on the north-east, but its banks do not coincide with the sides of the causeway across the ditch which encircles Stone henge. This suggests that it is a more recent structure. It con sists of a broad road with lateral ditches and a slight bank be tween road and ditch. From Stonehenge it runs a straight course for 1,70o ft. in a north-easterly direction. Then, according to Stukeley, it branches, one arm curving westwards to meet the Cursus, the other "directly east, pointing to an ancient ford of the river Avon." In 1921, by the aid of photographs from the air, Crawford was able to trace the continuation of the Avenue from its furthest fixed point on the ridge between the Old and New King Barrows to the Stonehenge-Amesbury road opposite West Amesbury Farm. These photographs were verified by ex cavation, and excavation has since traced the Avenue across the road to the farm buildings, but there are no indications either on the surface or on air-photographs that it was continued across the river. The air-photographs also tend to disprove the existence of a western branch. At its Stonehenge end the Avenue measures 72 ft. from ditch to ditch, but as it progresses it varies in width, and measures r ro1 ft. at West Amesbury.
Col. Hawley during his excavations for the Society of Anti quaries (192o-26) uncovered the eastern half of the ditch sur rounding Stonehenge, and cleared the north-eastern causeway, which was found to be studded with postholes. He also discovered a smaller southern causeway (Inigo Jones mentioned three cause ways, forming an equilateral triangle). The ditch is circular with a diameter of 30o ft., flat-bottomed, irregular, averages 5 ft. in depth, and has a bank on its inner side. The only objects found in its silting have been abundant red-deer antler picks, a few rough flint implements of Upper Palaeolithic facies, and two fragments of pottery. The chips of sarsen and bluestone struck off when the
stones were dressed and set in place, are restricted to the lower level of the turf mould above the chalk silting.
In all, Col. Hawley cleared that half of the area inside the ditch which lies east of a north and south diameter. He discovered three important new features: a circle of holes parallel with and close inside the ditch and named by him Aubrey Holes, in honour of John Aubrey who recorded certain depressions along this line ; and two new circles of holes, Z and Y, nearer to but still outside the outer sarsen circle. There are probably fifty-six Aubrey Holes, of which number thirty have been excavated. They are circular in plan, and average 3 ft. 8 in. in diameter and 2 ft. 81 in. in depth. A small amount of cremated human bones was found in most of them, usually in a small pocket by the side of the hole. Sarsen and bluestone chips were present throughout their filling, but evidence is lacking as to whether stones or posts once stood in them. The Z and Y holes were wedge-shaped with rectangular bottoms. The Y holes averaged 2 ft. I 1 1 in. in depth and 5 ft. 61 in. by 3 ft. 9 in. at the top. The Z holes averaged 3 ft. 6 in. in depth and 5 ft. 101 in. by 3 ft. 8 in. at the top. They were constructed after the erection of the outer sarsen circle, but in all probability no stone or post ever stood in them. The Hele Stone was found to have an encircling ditch, with postholes to the west of it and three other stone holes between it and Stone henge. The Slaughter Stone had been buried in its present position and no doubt once stood upright in a hole to the west of it. The isolated sarsen on the south-east just inside the ditch had no en circling ditch. The so-called "barrow" on the south in the line of the Aubrey Holes was not a barrow, but the site of an upright stone with encircling ditch. Between this "barrow" and the stone circles were numerous postholes, arid within the circles the ground was honeycombed with others. Some were as old as, or older than, the erection of Stonehenge, but the date of most of them is as uncertain as is their purpose.