80 GEOLOGY OF SOIL. 



terizes soil, which characterized rocks ; that is, great similar- 

 ity, but not identity, and it is on limited patches only, that 

 soil partakes decidedly of the character of the underlying 

 rocks. 



33. The extensive analyses of soil, executed by the geo- 

 logical surveyor of Massachusetts, taken from every variety 

 of rock formation, present a remarkable uniformity, both of 

 chemical constitution, and mineraloglcal composition of the 

 earthy ingredients. In one hundred and forty-six soils of 

 Massachusetts, the combinations of lime, clay, iron, &c., 

 estimated as in the state of bone-dust, are per 100 



parts, 0.859 



Similar matters in the state of plaster are per 100 



parts, 1.823 



The surveyor suggests the subtraction of -J from the amount 

 representing matters allied to bone-dust, to reduce that to 

 pure bone-earth. A less amount should be allowed in 

 the matters allied to plaster. If 31 per cent, be deducted 

 from the sum of the plaster and bone-dust, the result is 

 1.851. 



Lime, in the state of marble or limestone, was found in 

 fourteen of one hundred and forty-six soils. Except in 

 limestone regions, the natural existence of lime in the state 

 of marble or chalk in soil is very questionable. Adding its 

 average amount as found in the soil of Massachusetts, viz., 

 0.916, the result is, — lime in various forms, — 2.047, fine 

 earthy matter insoluble in weak acids, 89.305. What is 

 true of the soil of Massachutetts is true of all soil — great 

 similarity of its mineral constituents, both in kind and pro- 

 portion. This is the truth, deducible from the average re- 

 sults of analyses of soil from various parts of the world. 

 But it may be said that the above numbers have been 

 deduced from the results of the examination of a very lim- 



