122 SOIL PHYSICS AND MANAGEMENT 



10. How do clays differ from clay loams ? 



11. Distinguish between silt loams and loams. 



12. What are the classes of sands? 



13. Why should care be exercised in the selection of samples for study? 



14. Give the objects of a soil survey. 



15. Why should the surveyor examine the soils to a depth of 80 inches? 

 10. What is necessary to make the soil map valuable? 



17. What apparatus is necessary for the soil surveyor? 



18. How are samples taken? 



19. To what depth are they taken and what divisions are made? 



20. What precautions are to be observed in taking samples? 



21. What is a composite sample? 



22. What is the weight of the strata of peat ? Of sand ? 



REFERENCES 

 Soil Reports, Illinois Station. 



Field Operations of the Bureau of Soils, U. S. D. A. 

 Kentucky Station Bulletins 102, 193, 194, 195. 



Iowa Station Bulletin 82, 1905. Iowa Soil Survey Report, No. 1, 1917. 

 Soil Survey Reports. Wisconsin Survey Bulletins Nos. 28-40, 1913-14. 

 Ohio Reoonnoissance Soil Survey. Field Operations Bureau of Soils, 1912. 

 Missouri Station Research Bulletin 3, 1910. 



Pennsylvania Station Bulletin 132, Soils of Pennsylvania, 1914. 

 Michigan Geological and Biological Survey, Publication 7, Geological Series 



5; Publication 9, Geological Series 7. 

 Tennessee Station Bulletin, vol. x, No. 3, 1897. 



