124 THE CULTURE OF FARM CROPS. 



est to the farmer, who plows the soil and reaps his crops 

 from the land made rich by the remains of past ages of veg- 

 etable and animal life; and the history of which is recalled 

 as he turns up in his fields the fossil or stony remains cf creat- 

 ures which existed, we know not how many ages ago. 



The composition of the various rocks is of great interest 

 to the student, because, as the soil is formed from the rocks, 

 and its character is recognized by fragments of the prevail- 

 ing rocks of which it is made up, the nature of the soil is 

 necessarily similar to that of the rocks of which it consists. 

 This knowledge of the rocks is indispensable to farmers, for 

 without it they cannot know what they should of their soils, 

 and the adaptability of these to the crops which they grow. 

 For there are wheat lands ; corn lands ; grass lands ; soils 

 for fruit; for the vine; for the dairy; for sheep; and for 

 other special crops as hops, tobacco, &c., and a right choice 

 of land for a special purpose is indispensable to . successful 

 agriculture. 



Granite is the foundation rock of the globe. It is the 

 basis of the oldest mountain ranges whose granite peaks, 

 bare and rugged, point their pinnacles to the noon-day sun 

 and defy the foot 'of man to reach them. This rock is of 

 great importance in the formation of the soil ; for it contains 

 the most indispensable elements for vegetable growth ; viz : 

 silica; potash, alumina and soda; and in veins which are 

 contained in it, lime; magnesia; phosphoric acid; sulphur 

 and chlorine are found. Thus from this one rock and its 

 accompanying minerals may be furnished to the soil, every 

 inorganic element needed for the successful growth of crops. 

 It is made up of crystals of quartz, feldspar, and mica, ce- 

 mented together most compactly and making a rock of ex- 

 treme hardness. The quartz is the clear, ' glassy, white, 

 mineral ; which makes up the larger portion of the ordinary 

 sand ; the feldspar is a flesh colored, or white, milky col- 

 ored substance, softer than the quartz, and is usually in the 

 form of square or rhomboidal crystals ; the mica is in white 

 yellow or black scales. 



There are no richer soils than those derived from granite, 



