How old are roads?

One of the most difficult aspects of researching old roads is the issue of dating. The stretch illustrated above is now a footpath, but has clearly been a lane at some point, as the stone walls are 10 - 12 feet apart, wide enough for a cart. But how old are the walls? If the surrounding fields were created during eighteenth century enclosures, they will be about two hundred years old. But the track, or the route, may be much older. How can we be sure?

Appearances can be deceptive, and what looks like an old lane may have been created in the nineteenth century or even later. So there are really only two reliable methods of dating. The first, searching maps, is only effective for the past 250 years or so, since the first fairly accurate map of Derbyshire was drawn by Burdett in 1767. The second method, excavation, apart from being difficult to carry out, is only useful if there is something to find. Only Roman roads were properly engineered with layers of stone, gravel, ditches etc, so there is unlikely to be any physical evidence of an earlier trackway.

The section of the Portway shown above, called Islington Lane, running north between Winster and Elton, is shown on Burdett's map as a major route, and moreover a lead mine is shown by the road called 'Portaway'. This suggests that the mine was called after the road. 

In addition, near here a cross-section of the track has been excavated by members of the Wirksworth Roman Project,  who found strata suggesting a properly built road about 6 metres wide. If, as seems likely, this shows Roman construction, the question remains whether they built the road on virgin land or were improving an existing, possibly Bronze Age, routeway?