GEOLOGICAL ACTION OF WATER 39 



black soil, which has also disappeared from Mr. Jones' 

 cornfield ? We do not see it here, so we must go down to 

 the creek ; perhaps we shall find it there. 



Indeed, how muddy the water is ; it seems that a great 

 deal of fine, corn-land soil has been stirred into this water. 

 We will take a bottle of this water and stand it in a quiet 

 place. But do you think this fine, dark soil in the creek 

 comes from Mr. Jones' field? No, I think not; it came 

 from places farther up the creek. And where does it 

 go? 



Look sharply about you ; perhaps you can find the answer 

 then. John thinks he knows. Let us see what he has 

 found. In this small low place the muddy water stood for 

 some time, and there is some yet in the deepest place. See 

 how the soil is covered with a layer of fine mud. The 

 water could carry this along although its current was quite 

 slow, but when it became very slow or stood still, even this 

 fine material was dropped. 



We saw that the creek was quite muddy after the last 

 heavy rain, and just as muddy we should find the river into 

 which the creek empties. If you ever see some of our 

 largest rivers, you will find their water quite muddy. 



Streams always carry most material at the time of a 

 freshet or flood. Wherever they overflow a swamp, a 

 meadow, or dry land, their current slows up as the water 

 spreads out, and there some of the material is deposited. 

 The finer the material the farther it is carried, and the 

 very finest is not dropped before the river enters the 

 ocean. Here many large rivers, including the Mississippi, 

 form large deltas with the sediment they carry. The 

 delta of the Mississippi contains about fourteen thousand 

 square miles. You can easily see that all deltas are grow- 



Let the children see who can find the most species, and who can make 

 the prettiest bouquets of the ears or heads. 



