EARTH-WORMS. 



Fio. 8. SECTION. REDUCED TO HALT THE NATURAL SCALE, or THE 

 VEGETABLE MOLD IN A FIELD, DRAINED AND RECLAIMED FIF- 

 TELN YEARS PREVIOUSLY. A, turf; B, vegetable mold without 

 any stones ; C. mold with fragments of burned marl, coal-cin- 

 ders, and quartz-pebbles ; D, gab-soil of black, peaty sand, with 

 quartz-pebbles. 



Darwin's garden disappeared, in the coarse of 

 years, under an inch of mold with which the 

 worms covered it. 



A stone, sixty-four inches long, seventeen 

 inches broad, and from nine to ten inches thick, 

 part of the ruins of a lime-kiln that had been 

 torn down thirty-five years before, lay in a 

 field, its base sunk from one to two inches 



below the general level, while the 

 surface of the field for about nine 

 inches around it sloped up toward it 

 to the height of four inches above 

 the surrounding ground close to the 

 stone. (Fig. 4.) 



When the stone was removed, an 

 exact cast of its lower side, forming 

 a shallow crateriform hollow, was 

 left, the inner surface of which, ex- 

 cept where the base had been in con- 

 tact with brick rubbish, consisted of 

 fine black mold. The turf-covered 

 border, which sloped up to the stone, 

 consisted of fine vegetable mold, in 

 one part seven inches thick, and was 

 evidently derived from worm -cast- 

 ings, several of which had been re- 

 cently ejected. This stone would have 

 sunk to the level of the field in two 

 hundred and forty-seven years if none 

 of the castings were washed away by 

 rains. Some of the fallen stones at 

 Stonehenge have become buried to a 

 moderate depth in the ground, and 

 are surrounded by sloping borders of 

 turf, on which recent castings have 

 been seen. 



The estimates of the amount of 

 mold brought up by the worms, 

 based on actual weighings and meas- 

 urements of the castings at particular 

 spots, give results ranging from 7'56 to 18'12 

 tons per acre in one year, and a volume suffi- 

 cient to make when spread out a layer of soil 

 of from one to more than two inches thick in 

 ten years. The remains of ancient buildings 

 seem also to have been buried effectively, in 

 large part, through the action of worms. An 

 example of this kind is furnished at Abinger, 



Fio. 4. TRANSVERBK SECTION ACROSS A LARGE STONE WHICH HAD LAIN ON A GRASS-FIELD FOR THIRTY-FIVE 

 TEARS. A A, general level of the field. The underlying brick rubbish has not been represented. Scale, one 

 half inch to one foot. 



Surrey, where the remains of an ancient Roman 

 villa were discovered in 1877. The cut (Fig. 5) 

 represents the appearance presented by the 

 buried wall and the ground around it at a point 

 where one of the trenches was dug. The mold 

 here was from eleven to sixteen inches thick 

 over the tesselated floor, G, and from thirteen 

 to fifteen inches thick over the broken summit 

 of the wall, "W. No signs of worms appeared 

 on the trodden-down earth over the tesseras 

 when they were first cleared, but many signs 

 of fresh worm-action were seen on the next 

 day, and for the next seven weeks these signs 

 were very abundant. Numerous burrows were 



also found in the course of the digging, and 

 worms were brought up from a considerable 

 depth. Three years afterward the worms were 

 still at work, burrowing in the concrete floor 

 and the mortar of the walls. 



Other striking examples of the action of 

 worms are found in the ruins of the old Roman 

 town of Silchester, where the concrete floor of 

 the basilica, still covered here and there with 

 tessera, is found at three feet below the sur- 

 face. Worm-castings were observed on the 

 floors of several of the rooms, in one of which 

 the tesselation was unusually perfect. Open 

 worm-burrows were found beneath all the 



