1878. ] Phystography. 671 
And how comes it here? Directly or indirectly from rainfall. 
Whether its source be a spring, or the collected waters from a 
sloping hill-side, it matters not. Without rainfall, such as is now 
pouring from the distant storm-cloud, the streamlet could have 
had no existence. 
Another question therefore suggests itself: What is this rain- 
fall doing, and how comes it here? If we walk along the shore 
for a little distance, we may perhaps see (if there is beneath the 
cliffs any clayey material containing flat stones) small pillars of 
earth, each capped by one of these flat stones. These are little 
monuments of rain action. Rain falls upon the surface and runs 
off towards lower levels; as it runs, however, it carries with it a 
little of the fine clayey material. Thus it lowers the surface. But 
where there is a flat stone, the surface is protected from the soft- 
ening action of raindrops, just as a house is protected by its roof. 
The soil beneath the stone is not carried away, and the miniature 
earth pillar stands out as a monument. In Switzerland there are, 
in several places, earth pillars fifty or sixty feet high, which have 
been formed in this way. 
But it is not only where there are earth pillars that the rain is 
exercising a denuding action upon the land. If we go out into 
the fields on any rainy day, we may watch how the soil is liter- 
ally flowing downwards to the sea. Few fields are perfectly flat, 
and the rain which falls upon the surface tends to drain off at the 
lowest possible level. But if we examine the water which is thus 
on its way down the field, we shall at once see that it is not clear, 
that it carries with it some of the soil. Much of the rain, of 
course, sinks into the ground. But before it does so it is nearly 
sure to trickle a foot or two over the surface. Even if it only 
runs a few inches, it must bear with it some of the soil for this 
distance, and there leave it. If the rainfall continue, the soil is 
soon carried a few inches further; and it always travels in one 
direction from higher to lower levels. Our field may be separated 
at its lower end from another by a wall, which will check the 
downward progress of the soil. If this be so, we shall often find 
that, from the accumulation of this soil, a child may look over 
the wall on that side of it which faces up hill, while a full-grown 
man may have to stand on tiptoe to gain the same advantage on 
the lower side. Or perhaps at the bottom of the field there may 
be a ditch; that ditch may communicate with a streamlet, and the | 
