They have the appearance sometimes of shallow terraces raised one above the other, rising with the slope of the down. This terrace formation is perhaps occasionally artificial; but in some cases, I think, the natural conformation of the ground has been taken advantage of, having seen terraces where not the faintest trace of cultivation was visible. It is not always easy either to distinguish between the genuine enclosures of ancient days and the trenches left after the decay of comparatively modern fir-plantations, which it is usual to surround with a low mound and ditch. Long after the fir trees have died out the green mound remains; but there are rules by which the two, with a little care, may be distinguished. The ancient field, in the first place, is generally very much smaller; and there are usually three or four or more in close proximity, divided by the faint green ridges, sometimes roughly resembling in ground-plan the squares of a chess-board. The mound that once enclosed a fir-plantation is much higher, and would be noticed by the most casual observer. It encircles a wide area, often irregular in shape, oval or circular, and does not present the regular internal divisions of the other--which, indeed, would be unnecessary and out of place in a copse. It has become the fashion of recent years to break up the sward of the downs, to pare off the turf and burn it, and scatter the ashes over the soil newly turned up by the plough; the idea being mainly to keep more sheep by the aid of turnips and green crops than could be grazed upon the grass. In places it answers--in many others not; after two or three crops the yield sometimes falls to next to nothing. There is a ploughed field here right upon the ridge of the down, close to the ancient earthwork, where in dry summers I have seen ripening oats barely a foot high, and barley equally short. With all the resources of modern agriculture, artificial manure, deeper ploughing, and more complete cleaning, such results do not seem altogether commensurate with the labour bestowed. Of course it is not always so, else the enterprise would be at once abandoned. But when I come to think of the ancient tillage in the terraces upon the barren slopes, I find it difficult to see how, with their rude implements, the men of those times could have procured any sustenance from their soil, unless I suppose the conditions different.