ANALYSES OF DIABASE. 



357 



of the magnesia ; 45.88 per cent of the potash ; 95.37 per cent of the soda ; 

 42.40 per cent of the silica, and 21.38 per cent of the alumina have dis- 

 appeared. In the case of the granite, where the decomposition was much 



Analyses of fresh and decomposed Diabase from Spanish Guiana, Venezuela. 









S2 





§ 









oi g 



^ «^ 



t4-l '""' 









&JD ^ 



-*^ 



-tf 







TJ 



^j 



a 



P! 



Constituents. 









bJ0=3 



CO 











cS -1 



Qi -^ 



c5 -^^ 













G 02 





rd 



cp 



CD G 



CD a 





m 



Si 





 





if 



a3 ^ 





fa 



« 



Ph 



Ph 



P^ 



SiOo 



49.35 

 15 30 



43.38 

 18 36 



20.92 

 3 27 



57.60 



78 62 



42 40 



AI2O3 



21 38 



FgoOo 





20.39 



0.00 



100.00 



0.00 



FeO 



12.28 

 9.60 



"2.37 









CaO 



8.05 



16.17 



83.23 



MgO 



7.38 



3.45 



5.12 



30 ()3 



61 37 



K2O 



.85 

 1.98 



0.59 

 0.14 



0.33 



1.82 



54.12 

 4.63 



45.88 



]S[a,0 



95.37 



Ign 



3.25 



11.34 



4.18* 



228.62* 



0.00 









100.00 



100.00 



39.51 





Analyses of fresh and disintegrated Granite from the District of Columbia. 



Constituents. 



Silica (SiOa) , 



Alumina (AI2O3) 



Titanium oxide (TiOa) . ■ 

 Ferric oxide (Fe203) . . . . 

 Ferrous oxide (FeO). . . , 



Lime (CaO) . 



'Magnesia (MgO) 



Soda (Na20) 



Potash (K2O) 



Phosphoric acid (P2O5) . 

 Ignition .... 







69.61 

 14.39 



3.61 

 3.22 

 2.45 

 2.71 

 2.68 

 0.10 

 1.23 



100.00 



50 

 CD 



UJ 



O 

 a, 



a 



o 

 o 



Q 



65.84 



15.26 



0.31 



4.40 



2.64 

 2.65 

 2.12 

 2.00 

 0.06 

 4.72 



100.00 



^4 



U 02 

 ^ O 



cDj:=i 

 Pm 



10.50 

 0.46 



0.00 



0.81 



0.036 



0.77 



0.85 



0.04 



2.16* 



13.466 





<v 



(X) <v 

 fcJC P! 



?-< 

 <D 

 PM 



85.11 

 96.77 



100.00 



74.79 

 98.51 

 71.38 

 68.02 

 60.00 

 349.62^ 



<^ . 



OJ 02 



o 



^ o 

 a; ^ 



Pm 



14.89 

 3.23 



0.00 



25.21 

 1.49 

 28.62 

 31.98 

 40.00 

 0.00 



*Gain. 

 X LI— Bull. Geol. Soc. Am., Vol. 7, 1895. 



