ii
The Roman Road not only disappears through causes which I have called inexplicable and under the obvious influence of marsh or of cultivation, it also fell into disuse, even where it did not disappear, for reasons both explicable and inexplicable. There are cases where the falling into disuse is frankly not to be explained, though these I have found mainly upon the Continent. For instance, in the road from Rheims to Chalons you have the Roman road running almost parallel to the later road, the later trace having been made for no reason that we can discover—not serving any new towns or villages—a mere duplicate of the old way. But there are more cases where the disuse of a section of the Roman Road can clearly be explained by the need for visiting centres of population, production, and commerce. The Roman system for the serving of places off the main straight road was by side roads perpendicular to the main road. The relics of these you still see on many of the Continental roads—a direct perpendicular lane or avenue joining up the château and its dependencies or the neighbouring town with the main highway. When the Dark Ages came and the main roads degraded, the by-lanes and paths which had grown up as offshoots to them and which led to the estates and villages and towns and ports and quarries, etc., to one side or the other of the Road came to be used more frequently. The main travel between distant towns was less, the local travel grew more important in proportion. And as this development proceeded sections of the Roman Road tended to fall into disuse. The local roads would be maintained and the section of main road would be left unrepaired.
We have seen that the main cause of the breaking down of the Roman Road was marsh and the crossing of river valleys. Not only was this process true of natural marshes, especially at the sides of a river, it was true of a special case which is reproduced over and over again on the map of England, and for which I will take as a particular example a [very fine case near Norton Park], in Northamptonshire.
Part II, Sketch X
Here the Watling Street, the great Roman road from London to the north-west, crossed the valley of an insignificant stream; there was no marsh originally, and there is none to-day. There was only a small running of water, over which a culvert was thrown. The stream ran under the main Roman embankment through this culvert. Now, when the Dark Ages came and the roads fell into disrepair the first things to go, naturally, were the culverts. They got blocked up. Once they got blocked up the water dammed up on the higher side and began to undermine the embankment. By the time this had made the road, though still standing, impassable, travel had found a new way, usually down the stream away from the mere thus formed. Further centuries and the recovery of civilization cleared the ground: the embankment either was washed away or swallowed up in the mere and its subsequent marsh, the stream resumed its original course, the dry ground reappeared, but the trace of the Roman road upon either side across the depression was lost for ever and there was substituted for it the modern road, making a curve out of the direct line and only recovering it again after the obstacle had been passed.