EU TEC TICS IN ROCK MAGMAS 



89 



ANALYSES OF STONE FROM LIGHTHOUSE POINT, UNDER DIRECTION OF 

 E. D. CAMPBELL, BY E. E. WARE, JUNE 3O, I9O3. 



Distance from Margin 



Contact 



No. 



Mole- 

 cule 



616 mm 

 (2.2 feet) 



Mole- 

 cule 



4,115mm 

 (13.5 feet) 



Mole- 

 cule 



7,600 mm 

 (24.9 feet) 



No. 8 



Mole- 

 cule 



SiO 



AUO3 



FeoOj 



FeO 



MgO 



CaO 



Sodium oxide 



Potassium oxide 



\ H2O at above 800' C. 



) H.Oat 110° C 



COo" 



V„6^ 



s' 



CI 



MnO 



17-85 



3-13 



10.30 



(a) 7. 10 



(a) 8. 47 



2.04 



0.60 



(3) I. 97 



(a) I -55 



0.20 



0.143 



0.097 



0.07 



0.26 



0.783 

 0.175 

 0.019 

 o. 143 

 0.177 

 0.152 

 0.033 

 0.006 

 0.168 

 0.086 

 0.005 



O.OOI 



0.003 

 0.002 

 0.003 



47.67 



I7S5 

 2-Si 



12.59 

 5.65 



10.75 

 2,21 

 0.65 

 0.35 

 0.40 

 0.18 

 0.169 

 0.183 

 0.05 

 0.19 



0.795 

 0.172 

 0.016 

 0.17s 

 o. 141 

 o. 192 



0035 



0.007 



O. 112 



0.028 



0.004 



O.OOI 



0.0057 



0.0014 



0.003 



47.25 

 18.00 



12.42 

 6.35 



"•45 



0.158 

 0.086 

 0.02 

 0.18 



0.787 

 0.T76 

 0.014 

 0.172 



0.159 

 0.204 

 0.031 

 0.007 



47.10 



17-47 

 2.66 



12.93 

 6.88 



10.27 

 1. 91 

 0.59 



0.785 

 o. 172 

 0.017 

 0.179 

 0.172 

 0.183 

 0.031 

 0.006 



O.OOI 



0.003 



0.0025 



0.002 



100.760 



Ratio, alkalis; SiOo 



Ratio, pore space: solid space, 



in gasolene 



Sp. Gr. in gasolene 



0.048 



0.0473 

 2.83 



0.0012 

 3.02 



0.0483 



0.0032 

 3.01 



O.OOI! 



3.02 



(a) Checked later in another sample. 



(b) Determined on new sample, first method incorrect. 



labradorose as a limit up; and that those which occur with more 

 than 30 per cent, of magma belonging to the femic eutectic are 

 rare. 



Moreover, it will be noted that there is among the orders 

 between orders 4 and 5 a new principle of classification intro- 

 duced. This corresponds approximately to the extra alkaline 

 euLectics. Similarly, the rockallases appear very isolated and 

 strange in the salfemic family. 



I shall not, however, pretend to discuss the analcitic, melilitic, 

 and other alkaline eutectic magmas, with which Iddings is much 

 better acquainted than I. My object is rather to suggest that 

 ultimately a more rational and natural, and therefore useful, 

 classification of analyses might be attained if our main magmatic 

 groups were defined by the eutectic within whose influence they 

 come, so that in splitting one part will be nearer the eutectic and 

 the other farther from it. I have Iddings's diagram to thank for 

 this suggestion. 



