16 



AGRICULTURE. 



various sizes — pebbles, sand, clay, and vegetable mould- 

 in a candy-jar, and nearly filling the jar with water. 



(/') Now thoroughly stir the mixture, and allow it to 

 stand until the water clarifies. 



{c) Observe the arrangement of the sediment. Where 

 are the largest pebbles found ? Where the finest clay ? 



Of course the change here will be gradual, and 



■■T) 







•'"I. 



Kir,. 4 — DEPOSITION OF MATERIAL UPON SLACKING OF STREAM 



the layers will not be so distinct, as there was 

 no time for the formation of the stratificationif 

 plane between the depositions of different kinds 

 of sediment. 



(2) Underground Streams. — Part of the 

 water after a rain sinks into the ground. The 

 natural breaks in the rock serve as channels 

 which it may enlarge if the rock be soluble. 



