A study of this great earthwork proves that at some period of our history a resident people or a retiring nation wished to cut off the whole of south-west England from a northern enemy. To accomplish this purpose a huge bank with its ditch to the north was carried from near Portishead in Somerset right across Wiltshire, ending somewhere near Andover (Hants), between which place and the sea the low-lying watery valleys of the Anton and Test would in themselves be sufficient protection without an earthwork: thus the whole of the counties of Cornwall, Devon, and Dorset, together with parts of Wilts, Somerset, and Hampshire, were shut in and completely protected. After drawing the above line on a map it will at once be noticed that the usual rule of human effort—to do things with the least possible labour— has not been followed, as the left flank of the dyke, instead of resting on the Avon at or near Bath, has been at great labour carried across the stony Somerset hills to the open sea: this extra length was dictated by some powerful reason, the explanation being (as I read the evidence) that the enemy was in command of a fleet of small boats by which they could at any time land on the southern bank of the Avon (the Somerset shore). To guard against this the dyke Was built south of and above the Avon valley: we may suppose also that the invaders were without boats large enough to face the open sea or that the inhabitants of the Somerset and Devon shores were numerous or brave enough to defend themselves.