324 THE BOOK OF A NATURALIST 
appearance of a vast green serpent with its mile-long 
coil lying in a series of curves across the earth. As 
in the case of the old Roman green roads, the turf 
of the earthwork is a different and brighter shade 
of green than that of the valley. 
At this place I once met and had a long talk 
about the far past with a man of a singularly lively 
mind for a Wiltshire peasant. He told me that 
on numberless occasions since his boyhood he had 
stood looking at this great earthwork in wonder, 
asking himself who and what the people were that 
made it. “I have often,” he said, “had the idea 
that they must have been mad; for allowing that 
they had a use for such a wall and ditch why did 
they make it go winding all over the place instead 
of carrying it in a straight line and saving more than 
half the labour it cost to build it?” I could only 
suggest in reply that it was no doubt a very ancient 
earthwork, dating back to the time when metal tools 
were unknown in England and that the chalk had 
to be scooped up with sharp flints; that when they 
came to a very hard bit they had to make a bend 
to get round it. I also assured him that they could 
not have been mad as no such disease was known 
to the old ancient people. 
Now in spring the flat top of this earthwork in 
all that space where it lies across the level valley, 
the broad level top of the bank is grown over with 
the bird’s-foot trefoil, the yellow flowers as crowded 
as the daisies on the old Roman road, with not one 
flower to be seen growing on the green sloping 
