202 INTRODUCTION TO GENERAL SCIENCE 



the lighter varieties, forming sand dunes which often over- 

 whelm the fertile soils underneath, although, in time the 

 sand itself will make good soil. 



The transportation of soil by organisms has not, until 

 lately, been fully appreciated. The amount of earth which 

 is brought up by the earthworms is almost incredible, but 

 most of us are familiar with the disturbance of the ground by 

 moles and gophers. There are still smaller organisms, which 

 are invisible, that cause the material of which the soil is 

 composed to be more readily disintegrated, and carried away 

 by the other forces. Plants also move soils to a certain extent, 

 or so loosen them that they can be more readily moved by 

 wind or water. 



References : 



1. 1205 : 145-147. Transportation by the Wind. 



2. 1304 : 43. Residual and Transported Soils. 



3. 1601:50-54. The Work of Rain. 



4. 1601:54-61. Glacial Soils. 



5. 1601 : 61-64. Earthworms as Soil Workers, 

 a. 1302:113-114. Transportation by Glaciers. 

 6. 1303 : 136-138. The Wasting of the Lands. 



c. 1305 : 216-219. Transportation of Rock and Soil. 



d. 1309 : 146-150. Transportation and Deposition. 



e. 1311 : 87. Transported Waste. 

 /. 1604:41-49. Soil Carriers. 



g. 1604 : 63-68. Field Laborers. 



h. 1606 : 22-25. Transportation of Soils. 



i. 1612 : 17-22. The Soils that Living Things have Made. 



145. TEXTURE OP THE SOIL 



The size of the particles comprising the soil causes its, 

 various textures. Thus, if the particles are large, the soil 

 is said to be coarse, and, if they are small, we call the soil fine. 



