428 A. B. Lyons — Composition of Hawaiian Soils, 



seen ; occasionally there are masses, two to eight centimeters 

 or more^ in diameter of such crystals, and similar aggregations 

 sometimes of augite crystals. [These aggregations of crystals 

 are found, I believe, only in the tufa from the Salt Lake 

 region.] The fissures through which the materials of these 

 tufas were ejected, opened through the coral reef formation, 

 and so the tufa contains fragments of the coral rocks from the 

 size of a pin's head to that of a goose Qgg, The mingled 

 steam and carbonic acid forced up through the magma from 

 which the tufa consolidated, dissolved much of the lime of 

 this coral rock, depositing it again, partly in finely divided 

 state mingled with the mud in its superficial portions, chiefly 

 in crusts on the surface, or in veins occupying fissures in the 

 already consolidated rock. In the tufa of Punchbowl, No, 1, 

 this calcium carbonate has assumed a crystalline form, not only 

 in the joints of the tufa, but penetrating its substance through- 

 out. The regular calcite cleavage planes can be distinctly 

 seen on surfaces of fracture, although the calcium carbonate 

 amounts to no more than five to ten per cent of the rock. 



* 

 Table IV. Comparisons. 





Sound 

 Lava. 



Av. 



Tufa. 

 Av. 



" Kotten " 



Lava. 



Av. 



Soil. 

 Av. 



Punahou 

 Rock. 



Punahou 

 Son. 



SiOs 



TiOa 



1680 

 128 



1393 



320 

 110 



1 800§ 



1201 



97 



] 811§ 



AI2O3 ) * 



1000 



1000 



1000 



1000 



1000 



1000 



FeOf 



(156) 



(37) 



(35) 



not estim. 







MnO 



18 



10 



5 



4 



13 



5 



CaO 



303 



352:j: 





22 



404 



118 



MgO 



213 



358 



9 



20 



324 



71 



Na^O 



148 



66 



7 



(9)11 



208 



(24) 



K2O 



37 



30 





(8)11 



63 



(15) 



CuO 



•7 



3 



5 



not estim. 



8 



not estim. 



P2O5 



23 



23 



6 



12T 



37 



49 



SO3 



4 



4 



6 



4 



9 



4 



* The Fe203 includes total iron present. 



•f- Representing ferrous iron. 



X If tlie 3alcium present as carbonate (coral reef rock) be deducted, this figure 

 would be about 338. 



§ Insoluble residue, almost wholly SiOa and TiOa. 



|Na20 and K2O dissolved by boiling hydrochloric acid; the soil generally 

 contains a much larger amount, in the form of insoluble silicates. 



^In soils found from lapilli, the phosphoric acid is generally at least as high as 

 in the lapilli, illustrated in the Punahou soil in the table. 



Table lY sums up the conclusions to be drawn from these 

 analyses. Since the alumina and iron together constitute a 

 tolerably constant factor in the composition of the lava, and 

 are not liable to be dissolved out in appreciable quantity within 



