NATURE AND FORMATION OF SOILS. 27 



of the washing out of loose material, and of the cutting 

 power of water; of the abrasion performed by gravel, 

 pebbles, and stones. 



(c) Transportation Power of Water. Why is one 

 stream clear and another muddy? Note any sand or 

 soil dropped by water. 



( d) Note evidences of assorting power of water. 

 Draw a section of the bank of a stream, showing strati- 

 fication. 



(e) Note evidences of underground streams, of land- 

 slides, and describe and explain. 



(/) Frozen Water. Note work of frost, ice, glacier, 

 and snowslides. 



III. Organic Life. 



Everywhere myriads of living forms abound 

 in the air, in the water, on the land, and in 

 the soil. However, there must have been a 

 time when life did not exist upon the earth. It 

 must have begun in a very humble manner, be- 

 cause the early conditions were such that com- 

 plex organisms could not exist. 



It is believed by both geologists and embry- 

 ologists that from these simple beings have 

 evolved in succession, through vast ages of 

 time, all the higher and more complicated 

 forms. 



With the advent of life arose a new and 

 mighty potency in the work of soil formation, 

 and this force becomes the greater as life be- 

 comes more varied and complex. 



i. Plant Life. The fact that plants have 



