Chap. IV. OP ANCIENT BUILDINGS. 211 



and here there were worm-burrows. Mr. 

 Joyce and my sons were surprised at the 

 blackness of the mortar in this and in several 

 other cases, and at the presence of mould in 

 the interior of the walls. Some may have 

 been placed there by the old builders instead 

 of mortar ; but we should remember that 

 worms line their burrows with black humus. 

 Moreover open spaces would almost certainly 

 have been occasionally left between the large 

 irregular flints ; and these spaces, we may 

 feel sure, would be filled up by the worms 

 with their castings, as soon as they were able 

 to penetrate the wall. Rain-water, oozing 

 down the burrows would also carry fine 

 dark-coloured particles into every crevice. 

 Mr. Joyce was at first very sceptical about 

 the amount of work which I attributed to 

 worms ; but he ends his notes with reference 

 to the last-mentioned wall by saying, " This 

 " case caused me more surprise and brought 

 " more conviction to me than any other. I 

 " should have said, and did say, that it was 

 " quite impossible such a wall could have been 

 ■' penetrated by earth-worms." 



In almost all the rooms the pavement has 



