There are, along the sides of the Axe valley, examples of what geologists call remnant terraces. In an earlier age the valley floor and river lay at a higher level. Then, because the sea level fell, the river began to cut its valley down—that is, it cut a new trench, which gradually widened, but did not get as far as consuming the whole of the old valley floor. The terraces are remnants of the former higher plain. Axminster, or at least the old core of it, stands on one of these terraces, as if on a bench beside a road. The ways out of the town toward the river climb down the terrace side to the new plain: the flight of stairs near the post office, and Castle Hill, and West Street, though that mutes the descent by going at an angle.

The ancient Fosse Way, using the Axe valley to travel from central England to the sea, follows the terrace along the southeastern side, and so do the present roads irregularly following the Fosse Way through Axminster toward Musbury.

But, as a cyclist well knows who follows such a road, the terrace is not continuous: the valleys of side-streams cut across, making dips in the terrace and road.