26 SOIL PHYSICS AND MANAGEMENT 



the formation of soils, both in the breaking down of minerals and in 

 mixing of soil and subsoil. 



QUESTIONS 



1. Define weathering. 



2. Distinguish between the two forms. 



3. Does kaolin change into other minerals? Why? 



4. In what ways do heat and cold disintegrate rocks? 



5. Why does not a single hard freeze break all frozen rocks into fragments? 



6. Give the principal glacial areas of the present time. 



7. What is the law for the work of streams? 



8. Give some good local example of erosion. 



9. How do the waves do their work? 



10. Why is the wind such an effective erosive agent? 



11. What is the source of each of the acids that aid in weathering? 



12. Why does the soil air contain more carbon dioxide than the atmosphere? 



13. How does oxidation hasten the breaking down of rocks? 



14. Does deoxidation aid in mineral decomposition? 



15. Bring in a sample of feldspar that shows hydration. 



16. Calculate the percentage of lime lost from each rock given in table on 



page 22. 



17. Calculate the loss of magnesia in the same way. 



18. How are stalactites and stalagmites formed? 



19. Why are limestone soils so frequently acid? 



REFERENCES 



"American Journal of Science, volume xxii, 1832, p. 136. 



*Dutton, C. E.~ Tertiary History of the Grand C'anon of the Colorado. 



Merrill, G. P., Rocks, Rock- Weathering and Soils, 1906, p. 101. 



*Hilgard, E. W., Soils, 1906, p. 19. 



Johnson, How Crops Feed, 1910, p. 139. 



Merrill, G. P.. Rocks, Rock-Weathering and Soils, 1906, p. 166. 



7 American Journal of Science, volume v, 1848. 



Merrill, G. P., Rocks, Rock-Weathering and Soils, 1906 (Adapted), pp. 



195-202. 



Prestwich, Quarterly Journal Geological Society, volume xxii, p. 47. 

 "Reade, Liverpool Geological Society, 1876 and 1884. 



