504 H. S. JEVONS, H. I. JENSEN, T. G. TAYLOR AND C. A. SUSSMILCH. 



Quarry; and it was therefore taken from a zone higher up, 

 i.e. nearer the periphery of the mass, than specimen I, but 

 probably not so near the contact as specimen B. We reach 

 this conclusion both from a brief note by Mr. G. W. Card 

 which accompanies the analysis in which he describes the 

 specimen as megascopically "holocrystalline, black, even- 

 grained and somewhat compact," which accords well with 

 the character of the main mass of the rock exposed in the 

 Emu Quarry, and from a comparison of the analysis with 

 those of our specimens. Both the low specific gravity and 

 content of Ti0 2 show that the sample contained less 

 ilmenite than specimen I, which mineral, as we point out 

 later, decreases in abundance from the great segregation 

 veins upwards; and also it is intermediate between speci- 

 mens I and B in the percentages of silica, lime and the 

 alkalies. If, as we believe, the same vertical distribution 

 of the constituents may be assumed for the locality of the 

 Emu Quarry as is observed in the Reservoir Quarry, the 

 internal evidence is also in favour of the supposition that 

 the specimen came from the main mass of the Emu Quarry. 

 In column IV is stated au analysis of the aplite occurring 

 in the great veins of the Reservoir Quarry. It will be 

 discussed in the third part of the paper, but is stated here 

 for convenience in bringing all the complete analyses 

 together. 





I. 



II. 



III. 



IV. 



SiO a 



41*05 



43*06 



46-26 



58*82 



Al 2 O s 



1227 



16*31 



13-36 



16*91 



Fe 3 3 



6'39 



5*40 



2*34 



2-40 



FeO 



11*07 



7-61 



10*53 



4*59 



MgO 



6*38 



5*49 



8*87 



0-88 



OaO 



10*96 



9*37 



9*18 



2-42 



Na 2 



2*43 



3*12 



3*27 



6*74 



K.O 



0-53 



1-07 



1-23 



2*96 



H 2 Q (100° 0) 



0*44 



1-16 



0*15 



0*56 



