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of basalt, broken masses of such material containing 

 cavities in which steam and other gases were formed, or 

 finely divided volcanic cinder. From these materials, 

 the present agricultural soils have been formed by pro- 

 cesses of disintegration, due to chemical changes, the 

 effects of water; and the growth of plants. 



From the standpoint of geological chronology, the 

 Islands, as a whole, are relatively new; and the soils 

 have, therefore, not been subjected to as many changes 

 as have occurred in older agricultural regions. Our 

 soils differ greatly from those on the mainland, and can- 

 not be classified without considerable qualification in the 

 group names which have bewi adopted for mainland soils. 

 Our soils are, on the whole, exceedingly fertile, due partly 

 to the original abundant store of plant food in them, 

 and the relatively short period to which they have been 

 subjected to leaching. 



The soils of the Hawaiian Islands are sometimes classi- 

 fied, according to color, into red, yellow and black soils. 

 The red and yellow colors are due to the presence of iron 

 oxide, the yellow soils being more highly transformed 

 and somewhat less fertile than the red soils. The color 

 of our black soils is due to the presence of humus, mag- 

 netic iron oxide, or manganese. As a rule, the soil are 

 very deep, some of them being decomposed in place, while 

 others are partly the results of washing from higher 

 levels. Physically, our soils are characterized by the 

 large percentage of exceedingly fine granules. In some 

 localities, the fineness of the soils compares closely with 

 that of precipitated chalk, being almost an impalpable 

 powder. In other localities they show a large percentage 

 of granules, giving rise to the term "shotty" soils. Most 

 of our soils become sticky when wet, but readily disin- 

 tegrate again upon drying out. 



From a chemical standpoint, our soils are characterized 

 by the high content of Iron, which ranges from fifteen 

 to forty or sixty, and in exceptional cases, 80%. The 

 iron is present in all of the usual forms or oxide. The 

 content of phosphoric acid and nitrogen is relatively 

 high, but these elements are not always in the most 

 available form. Potash is present in about the same 

 • percentage as occurs on the mainland. Manganese is 

 found in our soils to a much higher degree than on the 

 mainland, constituting, in some of the black soils, as 

 much as ten per cent, of the total constituents. Titanium 

 IS also relatively abundant in the soils. Lime has been 



