EXERCISE 111 

 SOIL FORMATION BY WEATHERING 



Materials. Exposed rock surfaces, as cliffs ; rock and soil debris 

 at base of cliffs. 



Directions for work. Examine exposed rock surfaces carefully 

 to see whether by action of the atmosphere, water, frost, or 

 otherwise, small particles of rock are being loosened. Note also 

 whether larger pieces are being broken off by the expansion of 

 water upon . freezing in crevices. 



If a rock cliff is being studied, examine the heap of soil and 

 other debris resting against the base of the cliff in order to find 

 out if this debris (the talus slope) is composed of such materials 

 as are being weathered from the face of the cliff. 



In your opinion, based upon the facts discovered, has the 

 rock examined contributed to the formation of the soil in its 

 vicinity. 



References 



BERGEN and CALDWELL. Practical Botany, pp. 436, 437. 

 Textbooks of physiography. 



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