100 Bulletin 171. 



A. Reading-Lessons ]N"os. 1 and 2. 



LESSON NO. 1. THE SOIL : WHAT IT IS. 



1. The basis of soil is fragments of rock. — As the earth cooled, 

 the surface solidified into rock. The processes of nature have been 

 constantly at work in breaking up this rock and making it into soil. 



2. Weathering is the great agency in raahing rocks into soil. — ■ 

 Rain, snow, ice, frost have worn away the mountains and deposited 

 the fragments as soil. Probably as much material has been worn 

 away from the Alps as still remains, and this material now forms 

 much of the soil of Italy, Germany, France, Holland. Our own 

 mountains and hills have worn away in like manner. 



3. Weathering is still active. — All exposed rocks are wearing 

 away. Stones are growing smaller. The soil is pulverized by fall 

 j^lowing. 



1. The particles of soil are worn and transported hy water. — 

 Every stream carries away great quantities of soil and deposits it in 

 the shallows and the bays. After every rain, the streams and ponds 

 are muddy or roily. Observe the sediment or tine mud which 

 remains when a " mud-puddle '• dries up. The rivulet may carry 

 away tons of earth every year ; and this earth is deposited some- 

 where, and sometime it may, perhaps, come into use again for the 

 growing of plants. Many of our best and richest farm lands are the 

 deposits of former streams and lakes. Such lands are fine and silt- 

 like. Most lowlands belong to this category ; and even some of our 

 higher lands are formed from deposits from water. The mixed and 

 varied character of soils is largely due to the fact that they are the 

 results of transportation from diifercnt places. 



Observe the flat lands about lakes. These flats are formed by the 

 deposition of material from the surrounding highlands ; but they 

 are often exposed before their natural time by the lowering of the 

 water level in the lakes. All lakes and ponds are filling up. Kearly 

 every stream makes a delta at its mouth ; but if tlie stream into 

 which it empties is swift, the delta may be carried away. 



Observe, also, the broad rounded hillocks and knolls in valleys 

 and ravines. Many of them have attained their present form from 

 the action of moving water. 



