1890.] PUBLIC DOCUMENT — Xo. 4. 307 



ration. Save in rare cases, as in the blue-grass district of 

 Kentucky, where the soil is immediately underlaid by soft 

 fossiliferous limestone, which rapidly decays when stirred by 

 the plough, such soils, save for artificial processes of fertili- 

 zation, rapidly lose their crop-giving powers. On the other 

 hand, the soils of the glaciated districts having no such 

 harvest of plant food gathered during the geological ages, 

 though they give less considerable returns than the natural 

 soils, commonly maintain their productiveness, and grow 

 steadfastly better under a rational system of tillage, even 

 independent of ordinary manuring. The fact is, that these 

 glaciated soils have in the pebbles which abound in them a 

 constant source of refreshment and renewal, which has only 

 properly to be made avail of to add to their fertility. Well 

 commingled with vegetable matter, frequently stirred with 

 the plough to promote the disintegration of the fertilizing 

 bits, such soils, under reasonable treatment, may, though 

 never very fertile, grow better for ages of tillage. 



Even the neglect and maladministration of such soils does 

 not usually bring the same amount of damage that it does to 

 the earth in non-glaciated districts. It is almost impossible 

 by injudicious cropping to exhaust what fertility may be in 

 soils of glacial origin. A few years of fallow permits a 

 sufficient accumulation of material decayed from the surface 

 of the pebbles to afford a fresh supply of plant food. 



Another advantage arising from the peculiar structure of 

 glacial soils is, that they rarely wash away in the manner 

 frequently observed in other more normal soils. Thus, while 

 in Virginia, Kentucky, and the other States south of the 

 glacial belt, large areas of what were tilled fields have been 

 swept away with the streams, leaving either the bare rock or 

 the subsoil, such devastation is never seen in glaciated dis- 

 tricts. In a more extensive way, because of the more 

 continued tillage, a large part of the once fertile lands of 

 southern Europe have been reduced to the state of desert. 

 The freedom from washing away, characteristic of glaciated 

 soils, is primarily due to the fact that they have no subsoil. 

 The ground water sinks freely into their depths, and gradually 

 escapes by ill-defined springs to the drainage system of the 

 country. The result is, that, whereas in Virginia and Ken- 



