soils which were found to be easiest under foot. The A151 passes across two types of country, the upland and the fen. The highest point on it lies within a kilometre of its western end at 123 metres above mean sea level. It then passes across a gently sloping dissected plateau of Jurassic rocks capped in its highest parts by glacial clay. After about 16 kilometres, it enters the fen and is soon at about two metres, rising to three, nearer the coast. Description The Western End Having for some time, extended its influence by diplomacy and trade, The Roman Empire began to take control in Britain from the year 43. An important part of the means of control was the building of soundly-built roads, running directly between key places. This led the engineers to overcome all but the greatest obstacles rather than going round them. One result of this was that they built roads on soils which others would have avoided. When the Roman authorities had withdrawn from Britain and their roads wore out, people began to wander from the Roman road lines where they could find a more secure footing by taking another line. The Roman equivalent of the A1 was built to a very high standard, during the early years of Roman rule in Britain. The English successors of the Romans in Britain, called this road Ermine Street from their word for "soldier", compare the German personal name, Herman. The twenty kilometre length of Ermine Street, at roughly the centre of which, the line of the A151 lies, passed over chalky till (boulder clay) which is very sticky when wet. As the Ermine Street carriageway broke up, people sought easier going by moving down towards the small River Witham whose valley had been eroded through the till, into the Jurassic limestone below it. Thus, in 1756 when the Colsterworth to Bourne road was turnpiked, the toll road which was to become the A151 began at the crossroads in Colsterworth, further west than it now does, though the first toll gate noted by the 1824 Ordnance Survey map was about three kilometres from there. When the Colsterworth bypass was built, its southern half was placed virtually on the Ermine Street line so that now, while the A151 still begins at the A1, it is not at the old Great North Road but at Ermine Street, on the chalky