Purton's Two Bypasses
When you look at Purton on John Ogilby's 1675 map of the route from Oxford to Bristol, you notice that there is a bypass marked on the map, which provided an alternative route from one side of Purton to the other. This is possibly the first-ever mapped bypass in history!
The bypass mapped by Ogilby runs from Packhorse Corner to the north of Purton across to the bottom of Pavenhill, on the road out towards Malmesbury. On the Andrews & Drury map of 1770 (below) the route of the North Wessex Way is highlighted in yellow and the bypass in red.
This is possibly the route of the original Iron Age path, traversing round the north side of Purton before meeting the track that comes down from Ringsbury Camp (an Iron Age Hill Fort) at Restrop. If this is the case, then L-shaped diversion that takes the North Wessex Way up the hill into Purton may well be of Roman origin - the Romans did like 90 degree turns in their roads after all!
When you look closely at a modern map of Purton, you notice that there was a second bypass, running slightly further up the northern edge of Pavenhill (highlighted in blue on the map above).
Part of this route is a very straight and wide track across Purton Common . The two pictures below were taken in the 1980s, then the track was clear of the brambles that cover it today. You can see that it is a wide and significant thoroughfare across the common.
(Thank-you to Purton Museum for finding these photos)
When you walk along this path (it is a public footpath / bridleway), you notice that there are large stones set in the ground, running for hundreds of metres. No-one seems to know when or why these stones were put there, but they do look like the remains of some sort of paved pathway.
This would make sense that the southern route was paved; the more northerly bypass runs across the low ground, on clay soil. This would have been impassible in the winter, and even in the summer, it would have been hard going after a period of rain. The other bypass is slightly further up the hill, well drained and with evidence of a paved surface. This would have made the second bypass much less weather dependent.
One final thought; could the origin of Pavenhill, the hill round the north side of Purton, be because it was, in fact, a paved hill?