382 THE BEGOLITH 



importance of the worms, both as mellowers of the soil and as 

 levellers of inequalities is therefore very great, and cannot be 

 overlooked here. 



"While the main influence of the worm is manifested in a 

 mellowing by burrowing and a transfer of material from a 

 lower to a higher level, they bring about a slight admixture 

 of organic matter through a habit of coming to the surface at 

 night time, and dragging down into their burrows small shreds 

 of leaves and grass, which, taken into account in connection with 

 the exerementitious matter of the worms themselves, must tend, 

 though it may be ever so slightly, to enrich the soil. The sub- 

 ject should not be dropped without referring to the abundance 

 of these worms, which in England has been estimated as at the 

 rate of 53,767 to each acre of garden land, and about one-half 

 that number for pasture land. It is scarcely necessary to re- 

 mark that their distribution is very unequal throughout the 

 world, and that in dry sandy regions they are almost, if not 

 whoU;, unknown. 



In northern temperate climates, such as that of New England, 

 and particularly where the soil is of a clayey nature like the 

 ground moraine, the burying action of the earthworm, as de- 

 scribed above, may be wholly overcome through the heaving 

 action of frost. Every farmer boy who has been condemned 

 to pick the drift boulders from a field knows through bitter 

 experience that, however well he may do his work in the fall, 

 however clean the surface may be when winter sets in, the fol- 

 lowing spring, after the frost is out of the ground, will find a 

 new crop in no way distinguishable from the old, which, for 

 all that he can see, may have rained down during the win- 

 ter's storms. The fact is, however, that they have been actually 

 thrown up, '* heaved out," the farmers will say, from below the 

 surface by the frost which here penetrates to a depth of two or 

 more feet. As the water-soaked clay underlying one of these 

 buried boulders freezes, it expands upwards, since this is the 

 direction of least resistance. The stone is carried up bodily for a 

 distance dependent on the amount of expansion. When the 

 frost leaves the ground, the soil sinks back nearly to its first 

 position; but the boulder never quite regains its former place, 

 being prevented by particles of soil, or clay or pebbles which fall 

 into the cavity as the soil shrinks away from it. The amount of 

 actual lifting for each season may be but slight, but as the 



