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 in 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 



