THE CONTENTS OF THE SOIL 23 



soil. Some lands have very porous or "rotten" 

 stones, and these pass quickly into soil. Stones 

 are no doubt a useful reserve force in farm 

 lands, giving up their fertility very gradually, 

 and thereby saving some of the wastefulness of 

 careless husbandry. The general tendency, in 

 nature, is for soils to become finer, more homo- 

 geneous, and better for the growth of plants. 



37. But there are greater movements than 

 these. Soil is often transported long distances, 

 chiefly by means of three agents: moving water, 

 ice and snow, wind. Transported soils are apt 

 to be very unlike the underlying rock (or origi- 

 nal surface), and they are often very hetero- 

 geneous or conglomerate in character. Soils 

 which remain where they are formed (27) 

 naturally partake of the nature of the bed- 

 rock, and are generally more homogeneous than 

 transported soils, as, for example, the limestone 

 soils which overlie great deposits of lime -rock. 



38. Moving water always moves land. The 

 beating of waves wears away rocks and stones 

 and breaks up debris, and deposits the mass on 

 or near the shore. Streams carry soils long 

 distances. The particles may be in a state of 

 suspension in the water, and be precipitated in 

 the quieter parts of the stream or in bayous or 

 lagoons, or they may be driven along the bed 

 of the stream by the force of the current, and 



