GEEENE COUNTY. ft«3 



sand, clay and vegetable mold. The whole substance of the soil is 

 honeycombed by their agencies and rendered vastly more permeable to 

 air and water To them, indeed, the fineness and homogeneity of the sur- 

 face are argely due. Whoever thinks this agency an insignificant one 

 has but to examine carefully the surface of any square rod of ground in 

 ear y summer to be convinced of his mistake. Such an examination 

 will show to any one who has eyes to see that an enormous amount of 

 mechanical labor, most useful in its results to man, is being performed by 

 these despised insects. The porosity of the ground, which is partly due 

 to these agencies, is illustrated in the well known fact that the earth 

 taken out from an excavation will never fill the space from which it has 

 been removed. But the porosity that nature gives to soils is not pro- 

 duced in a day. It is the result of these seemingly insignificant agencies 

 extended through periods of time sufiieiently long. 



This stratum of soil, thus prepared, is the sole dependence of the brick- 

 kilns which are possible in almost every square mile of the surface of 

 the county, and from it brick of excellent quality are cheaply produced. 



Mention has thus far been made of the formation of soils from the 

 bowlder clay alone, but processes precisely similar to those already de- 

 scribed, only far more rapid in their action, are going on in the beds of 

 modified or stratified Drift which make so important an element in the 

 surface of the county. The opening of every gravel bank shows these 

 processes with the greatest distinctness. The solution of the limestone 

 pebbles has been carried on for one or two feet below the surface until 

 most of them have entirely disappeared, the only pebbles that remain 

 being the hard and stubborn greenstones and granites of northern origin. 

 Vegetable mold has been mingled with these weathering products to 

 the same depth to which the solution has advanced, and thus the 

 boundary line between the soil and what it covers is marked by color as 

 well as texture. The incipient stages of the solution of limestone peb- 

 bles can be seen below this boundary in the softened and corroded sur- 

 faces which they show, but the mass below is, after all, a gravel bank 

 . and not soil. 



(6.) Varieties. The soils of the county may be divided into the follow- 

 ing classes, which will be readily recognized by those familiar with the 

 area under consideration : 



1. The valley soils, consisting principally of the first and second bot- 

 tom lands. 



2. The soils formed from the high level gravels. 



3. The yellow and white clays, the common upland soils of the county. 



4. The black uplands or blue grass land, most largely shown in Ross, 



