Geology of Mount Macedon. 217 



Fig. 2. — Alkaline-andesite, with altered olivine. Quarry in 

 north-eastern corner of parish of Woodend. Ord. 

 light. X 28 dia. 



Plate XVI. 



Fig. 1. — Hypersthene-biotite-dacite. Near the Landslip, 



northern face of Mount Dandenong. Crossed 

 nicols. X 26 dia. 

 „ 2' — Hypersthene-biotite-dacite, with broken and corroded 

 quartz crystal. Mount Dandenong. Ord. light. 

 X 15 dia. 



Plate XVII. 



Fig. 1. — Trachy-phonolite. Turritable Waterfall, Macedon. 

 Ord. light. X 28 dia. 

 „ 2. — Solvsbergite. Southern side of Camel's Hump. Ord. 

 light. X 25 dia. 



APPENDIX. 



Specific Gravities of the Felspars of the Macedon Area. 

 By H. J. GRAYSON. 



1. Geburite-Dacite - Willimigongong Creek, compact var. - 3'58-2-60 



2. Trachy-phonolite - Turritable Waterfall-tuff like - - 2-59-2-60 



3. Andesite - - - Hill, North-west of Newham - - - 2-59-2-60 



4. Solvsbergite - - Camel's Hump 2'58 



5. Greburite-Dacite - Cherokee-Koadside Boulder - - - 2"62 



6. Solvsbergite - - South side of Camel's Hump- - - 2'51-2*52 



7. Solvsbergite - - Hanging Eock, hard type - - - 2-58-2-59 



8. Geburite-Dacite - Summit of Mount Towi-ong . - - 2-68 



9. Trachy-phonolite - Turritable Waterfall, compact var. - 2'58-2-59 

 10, Solvsbergite - - Hanging Eock, soft type - - - - 2-o7-2-59 



The specific gravities were determined with the Thoulet solu- 

 tion of mercuric and potassium iodides. The crystals in the case 

 of Nos. 1, 3, 4 and 9 were clear, compact and free foreign matter. 

 Nos. 2, 5, 6, 7, 8 and 10 were in some instances weathered or 

 more or less aflected by impurities. 



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