THE LAY OF THE LAND 139 
Outspread before us as we look abroad over the landscape, 
with its levels of checkered fields, its patched and pie-bald 
hills, its willow-bordered streams and reedy swales, is this 
blanket of soil, which seems so permanent, yet which is 
forever shifting to lower levels. 
Water, descending, follows the lines of least resistance. 
Hence, from every high point, slopes fall away in all direc- 
tions. Some are turned southward toward the sun, and 
are outspread in fields that are warm and dry; others face 
the north, and receive the sun’s rays more obliquely, and are 
shadowy, moist, and cool. Some are exposed to the sweep of 
the prevailing wintry winds; others are sheltered therefrom. 
Some are high and dry; others are low and moist. 
Nature has her own crops, suited to each situation; sedges 
where it is wet; grasses where it is dry; spike-nard in the 
shade; clovers in the sun. None of them alone (as we raise’ 
plants) nor in rectangular fields, but each commingled with 
others of like requirements, and each distributed according 
to conditions of soil, moisture and exposure. One may see 
how nature disposes them by comparing the life in wet marsh 
and dry upland; or that of sunny and shaded sides of a 
wooded glen. 
Under natural conditions the soil of the gentler slopes 
remains in comparative rest, for it is held together by a net- 
work of roots of living plants; these never (except under 
the plow) let go all at once. One dies here and there, now 
and then, and adds its contribution of humus to the topmost 
soil layer. Under natural management, the fields are 
permanently occupied and never exhausted. The richness 
of the soil is ever increasing. Our stirring of the top soil 
enormously accelerates erosion. Our four-square fields 
and cross-lot tillage are well enough on the upland and low- 
land levels where conditions are fairly uniform and the 
loosened topsoil cannot slip away into the stream; but 
