WHAT SOILS ARE BEST FOR AGRICULTURE? 247 



4. (a) Make a trip into the country to study the effect of water 

 erosion. How do gullies which have recently been made differ 

 from the older ones in shape? Make two cross-sections on graph 

 paper for your notebook to show this difference. If you live in 

 a hilly country, try to see if all you noted in the gully can be applied 

 to the valleys cut by streams between the hills. 



(6) Make several excursions into the surrounding country and 

 try to find as many effects of weathering as you can. Write up 

 your findings in your notebook. 



5. Show in any way you can that soil is a mixture and not a 

 chemical compound. 



SCIENCE CLUB ACTIVITIES 



1. Have a meeting devoted to a field trip. Collect different 

 specimens of rock found in your community. Bring them, and 

 any other specimens of rocks which you may have, to school for 

 laboratory study. Record in your notebook where each specimen 

 was found. If you live in a part of the country where rocks are 

 abundant, note where they come out of the ground. Do they 

 lie in layers? If so, look for the remains of impressions of plants 

 and animals in them. 



2. Organize a collecting trip to get rocks and minerals for the 

 school museum. Label and classify them. 



3. If you live in a region containing sand dunes, make a field 

 trip out there and report back to the club on how dunes are built, 



4. Plan a meeting at which the program will consist of reports 

 made by teachers or pupils who have visited some of the National 

 Parks. 



REFERENCE READING 



Bradley, J. H., Earth and Its History. Ginn, 1928. Surface destruc- 

 tion, page 36 ; Rocks, page 176 ; Fossils, page 270. 



Cole, G. A. J., Rocks and Their Origins. Macmillan, 1923. 



Fairbanks, H. W., Stories of Rocks and Minerals. Educational Pub. 

 Co., 1926. Origin of rocks, pages 9-19 ; Erosion, pages 23-27 ; 

 Fossils, pages 76-87. 



Hawkeworth, H., Adventures of a Grain of Dust. Scribner's, 1922. 



Hawkeworth, H., Strange Adventures of a Pebble. Scribner's, 1921. 



Hotchkiss, W. 0., The Story of a Billion Years. Williams and Wilkins, 

 1932. 



Reed, W. M., The Earth for Sam. Harcourt, Brace, 1930. Chapters 

 V and X. 



Washburne, H., and Reed, F., The Story of the Earth and Sky. Century, 

 1933. Parti. 



