352 Junior Naturalist Monthly. 



THE FORMATION OF SOIL. 



G. F. Warren. 



The brook in the picture is "clear as crystal/' so that you could 

 see yourself in it. Are the brooks near your house always clear? 

 Usually in the spring and after heavy rains the streams are all roily. 

 Sometimes a stream comes out into a level place and runs so slowly 

 that it deposits the silt and makes soil. Some soils were made in 

 other ways. Long agO; before men lived here, a sheet of ice moved 

 over what is now New York State. This mass of ice was so thick 

 and heavy that it ground some of the rocks into sand and soil. This 

 period was called the glacial period. Perhaps you can get some one 

 to tell you more about it. But the most important way in which soil 

 is being formed is going on all about us. It is so slow a process that 

 you have probably never seen it. Did you ever see a " rotten stone," 

 that is, one that would break to pieces very easily? Perhaps you 

 have seen the tombstones in an old graveyard crumbling to pieces. 

 What do you think makes them crumble? In time would one of 

 them make a soil? 



If you have a magnifying glass, examine some sand and fine soil 

 with it. Notice that the grains of sand or clay, when magnified, look 

 like rocks. 



Are there any stones in the soil around yoiu* home? How did 

 they get there? Were they brought by streams or glaciers, or are 

 they parts of the rocks that were originally there and that have not 

 yet crumbled into small enough pieces to be called soil? If the 

 stones are rounded, tell how you think they became so. How was 

 the soil around your schoolhouse formed? Was it deposited by a 

 stream or glacier, or how did it get there? 



Sometimes the soil is washed away as fast as it is formed, so that 

 the bare rocks are exposed. Do you know of any place where the 

 rocks are not covered with soil? Do you know of any stream that 

 has a rock or stone bottom? 



Soil is always being washed from the higher points of the field to 

 the lower parts. Which are the more fertle, the lower lands or the 

 higher ones? What effect does it have on the fertility of a field when 

 the soil "washes"? In the south, farmers sometimes plow and plant 

 aroimd a hill rather than go up and do^^^l it, and they leave a strip 

 of un plowed land every few rods. The water then has to run cross- 

 wise of the rows and furrows, and across the unplowed strips of grass 

 land, so the soil cannot wash badly. This is called "contour farm- 

 ing." Our soils do not wash so badly, but still there is much loss. 



