40 SOIL PHYSICS AND MANAGEMENT 



seen along the tributaries of the Mississippi and Wabash Rivers. 

 The very heavy soils along these have been formed in this way. 



QUESTIONS 



1. What are sedentary formations? 



2. Distinguish between residual and cumulose soils. 



3. Give history of an ox-bow lake; its formation and filling. 



4. Give four ways in which lakes may become extinct. 



5. What conditions give rise to peat? 



6. How is peat formed? 



7. What is a climbing bog and how formed? 



8. How may a wet woods become a swamp ? 



9. Draw a diagram showing how ablation swamps may be formed. 



10. How are colluvial soils formed? 



11. What is meant by the "creep" of material on hillsides? 



12. What are the laws for the carrying power of running water. 



13. Give an example of this power. 



14. What is the specific gravity of a soil particle .01 mm. in diameter and 



its inclosing film of water .05 mm. thick? 



c, y^ 15. How long would be required for the Potomac River to remove 12 inches' 

 of material from its drainage basin at the rate given in table p. 35? 



16. W 7 hat are the divisions made of marshes? 



17. What are the forms of lacustrine deposits? 



18. How are terraces formed? 



REFERENCES 



1 Marbut, C. F., Bennett, H. H., Lapham, J. E., and Lapham, M. H., Bulletin 



96, Bureau of Soils, U. S. D. A., 1!)13, p. 10. 

 1 Deacon, G. F., Inst. Civil Engineering Proceedings, volume 118, 1894, 



p. 93-96. 



*Geikie, Textbook of Geology, 3rd edition. 

 *King, F. H., Suspension of Solids in Fluids and the Nature of Colloids 



and Solutions, Transactions Wisconsin Acad. Sci., Arts and Letters, 



volume 16, part 1, 1908. 

 Babb, Science, volume 21, 1893, p. 343. 



General References. McGee, W. J., Bulletin 7'1, Bureau of Soils, 

 U.S.D.A., 1911, Soil Erosion. Davis, R. O. E., Bulletin 180, U.S.D.A., 1915, 

 Soil Erosion in the South. Salisbury, R. D., Agencies which Transport 

 Material on the Earth's Surface, Journal of Geology, volume iii, p. 170. 



