The megalithic was the most visible of several phases of building types, only recently identified as the actual built heritage of the British "neolithic" period; that is, between the widespread building of long and round barrows and the last stone circles in Britain. Avebury and Stonehenge were just starting to be built as stone circles towards the end of the main Cursus-building period, dated as between 3600 and 2800 BC.

Stonehenge Cursus

Figure 1 The Stonehenge Cursus viewed from its eastern end. The gap in the trees on the horizon marks its western end.

This period of earthworks are exemplified by the cursuses (plural) around Stonehenge (Figure 1) and Avebury. In essence they were an aligned strip of land demarked by either a bank, a ditch or, only occasionally, post-holes. The most common forms are rectangular with rounded (type A) or square (Type B) ends. The first to document those surviving near Stonehenge and Avebury was Lincolnshire doctor William Stukesley. He discovered the ditched Avenue running along the midsummer sunrise alignment to Stonehenge (starting at the Heel Stone) but, more observantly (says Roy Loveday in his book), he spotted what he called (and we therefore now call) The Cursus (a Roman word for racetrack). He appears to have adapted his field drawing to suit by rounding its square ends so that chariots could have turned around, in his 1740 Stonehenge, a Temple Restor'd to the British Druids (Figure 2). This has a bearing on how early antiquarians were following the notion that everything began in the Iron Age, and readers may also find it entertaining to read my article on Fields, Racetracks and Temples in Ancient Greece.

Stukesley Cursus comparison

Figure 2 Stukesley's rendition of The Cursus near Stonehenge.
The field sketch clearly shows a rounded but square end (Type B)

When Stonehenge came to have a cursus (the Avenue) protruding towards the summer sun. Stonehenge 1 (ca.3100 BC) is  a set of 56 pits in the chalk, probably set with 56 bluestones in an original and accurate stone circle, set a circular earthwork. The Avenue is stated to have been added during Stonehenge 3 part II (ca. 2600 BC), having a near trackway from the river Avon and then a direct and accurate uphill course to Stonehenge symbolising the midsummer sun. The Avenue therefore demonstrates a very likely usage for cursuses in general - that they may often have reflected the solar or lunar extremes on the horizon at their latitude, a function taken over by the use of standing stones perhaps to increase the accuracy of those alignments. Alexander Thom counted some smaller monuments as symbolic rather than exact, for example the Crucuno rectangle and Castle Rigg whilst he demonstrated how longer alignments to foresights could embody exact azimuths to horizon events. I have also found the cursus and triple henge monument at Thornborough (3500-2500 BC) was aligned to the moon on the horizon as it approached its extreme northerly moonset in the northwest.

It is aerial photography which has revealed that curcus-and-henge building was the norm before stone circles such as Stonehenge (bank then ditch perimeter) and Avebury (a true ditch->bank perimeter henge). "When in 1922 Air Commedore Clark Hall noted strange marks that proved to be Celtic fields on RAF aerial photographs of the downs near Winchester archaeology broke free from the spade and the vagaries of historical land use." Loveday, p18. Note the term Celtic fields which, like Roman cursuses, truncated evidence to being of the iron age. Over 100 possible cursus sites have now been identified.

MajorAllensPhotograph

Figure 3 The first aerial crop mark of a cursus from Loveday 2006

Our view of the prehistory of England is that a well-established cursus culture evolved into the megalithic culture which built Stonehenge 1 and Avebury stone circles. Another precursor must be the megalithic in West Wales and in particular the Preseli Hills which brought the bluestones to Stonehenge 1. The most famous monument remaining from the Preseli megalithic culture is the Pentre Ifan dolmen (ca. 3,500 BC) and the precedent for that culture has to be Ireland and Brittany, especially the Mobihan area (of Carnac fame), and this implies that the megalithic culture came to a Britain that was a cursus culture. But the cursus culture is really an alignment culture without the stone monuments, sharing the principle uses of metrology, geometry and astronomical counting. The monuments around Carnac, from as early as 4800 to 3000 BC, express so many of the forms later monuments would take: dolmens; egg-shaped and flattened circles; cairns; earthworks and barrows; alignments to menhirs and extremes of the sun and moon; stone rows, squares, rectangles and quadrilaterals. Some of these do not reach Britain and indeed some may have been unique monuments that were replaced by numerical or geometrical know-how. 

It is clear that alignments to horizon events informed the cursus culture and it may be this that led to the discovery of alignments in the last century, found on Britain's Ordnance Survey maps, reported in Watkins Old Straight Track and Michell's The View over AtlantisIn City of Revelation John Michell says:

A mystery too deep for present inquiry concerns the ancient geographical arrangement of temples in relation to each other. That there was some esoteric scheme linking the various centres has always been an item of occult tradition, and the idea is supported  by the discovery of identical figures of numerology in all cosmic temples; but the first modern indication of a planned location of ancient sites was provided by Alfred Watkins in his principal work, The Old Straight Track, first published in 1925, and recently repub­lished. Scarcely anything is now known of the aims and methods of this forgotten science, whose monuments are the relics of a neolithic world civilisation. 

Only aerial photography could unlock, by the 21st century, the full extent of the earthworks culture of Britain which Google Earth is now opening up also in the Americas, where the Hopewell earthworks (aligned to sun and moon) in North America, joined by a similar expression beneath large sqathes of deforested Amazon rain-forest. The components of Britain's "luney fringe" or "2nd Romantic Age" (Ron Hutton) of the late 20th century should be reviewed in the light of these dominant cultures of British prehistory who built earthworks and megaliths organised according to alignments, puctuated by monuments. In this website, the category Landforms was developed as necessary to cope with those manifestations of the ancient number sciences which had created extensive structures upon the land, long before Plato, Euclid or Ptolomy's geometry. John Michell's deduction of a large decagon of "holy choirs" for example, if real, is probably pre-Roman.

According to Loveday (summarising pages 9-10,) archaeology has now found a timeline for Britain of

  1. 4000-3400 BC Early Neolithic - agriculture, long barrows and enclosures.
  2. 3600-2800 BC Middle Neolithic - round barrows and colinear cursuses (Peterborough ware).
  3. 2800-2200 Late Neolithic -  circular henge, post and stone circles (Grooved ware)
  4. 2400-1600 BC - round barrow reappears (Beakers)

 But the latter half of phase 2 saw the start of phase 3, in Stonehenge 1 and Avebury, clearly in response to a preexisting West Wales (3500 BC) and Cumbrian megalithism (Castle Rigg, probably 3200 BC, is aligned to Long Meg). At the same time Gavrinis Cairn was closed and the Boyne culture of chambered tombs (fl. 3200 BC). It would seem quite wrong not to connect the entrance of megalithism into England with what was happening in Brittany, Ireland and West Wales and see that the cursus culture was a compatible cultural form.