348 THE BOOK OF A NATURALIST 
Silchester, when year after year the pavements and 
floors and foundations of houses and temples and 
public and private baths were uncovered until the 
entire 200 acres within the walls had been dis- 
closed. It is not necessary to describe here, since 
we have it all in Darwin, just how the worms 
succeeded in burying in a century or two all that 
remained of a ruined Silchester—the outside wall 
excepted—to a depth of three to four feet beneath 
the surface. We know that for the last 800 years 
the ground has been cultivated above the buried 
city. When watching these excavations I dis- 
covered one fact about worms which Darwin 
missed. Among the best finds at Silchester were 
the large and in some cases uninjured mosaic 
floors of the more important houses, some of 
which were removed intact to Reading Museum, 
and may be seen there. 
When one of these fine large floors was un- 
covered it remained im situ until the late autumn, 
when it was taken up and removed. Observing 
these floors, after they had been washed and scrubbed 
until they looked as fresh as if made yesterday 
instead of nigh on twenty centuries ago, it surprised 
me to find that worms were quite abundant beneath 
them, that they came to the surface through small 
borings which were not noticed unless closely 
looked for; they came up by night, and in the 
morning the workmen had to sweep the castings 
away to make the floors clean. The question that 
suggested itself was: Why did the worms continue 
