Geology of LUydale. ;i65- 



]."). Skeats. E. W.. and Smunicrs, H. S. "The (ieology and 



Petrology of the MiUL'don District. Bulletin of the Geol. 



Surv. of Vic. 11)12. 

 M). Kichards, H. (_'. " On llif Separation and Analysis of 



Minerals in the Dacite of Mt. Dandenong, Victoria." Proe. 



Roy. Soc, Vic, n.s.. Vol. xxi.. Pt. ii.. Pp. 528-5:19, 1909. 



17. (Iriffiths. G. S. "The Geology of Mell)ourne."' A.A.A.S. 



Handbook of Melbourne (1890) ,Mtg., P. ;}8. 



18. Jutson, J. T. " A Contribution to the Physiography of the- 



Yarra Kiver and Dandenong Ck. Basins. Victoria." Prnc. 

 Roy. Soc. Vic, Vol. xxiii.. New Series. Pt. i.. 1911. 

 l;). Harker. A. "The Natural History of Igneous Rocks. 19()!>. 



20. Hatch. F. H. "Text Book of Petrology." 1909. 



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 Pp. l-ll. 



IX.— DESCRIPTION OF PLATES. 



Plate XXIX. 



Fig. 1. — Photomicrograph of tlie Lower Toscanite Series, x 29, 



polarised light, showing ground-mass composed of ortho- 



dase, and microlites of plagioclase. the latter with parallel 



arrangement. 

 Fig. 2. — Photomicrograph of the Upper- Toscanite Series, x 29, 



polarised light, showing microcrvstalline ground-mass, and 



the jjarallel arrangement of the phenocrysts of plagioclass 



with the few microlites that occur. 

 Fig. 3. — Photomicrograph of the Lower Dacite Series, x 21, 



polarised light, showing fiactured phenocrysts of quartz. 



orthoclase, plagioclase. and biotite set in a glassy base; 



also showing an included fragment of hornfels. 

 Fig. 4. — Photomicrograph of the Middle Dacite Series, x 21, 



polarised light, showing phenocrysts of quartz, felspar. 



and biotite. in a fine ground-mass, shimmering with 



biotite. 

 Fig. 5. — Photomicrograpli uf a granodiorite porphyry dyke. 



X 21, polarised light, showing phenocrysts of biotite 



and zoned plagioclase set in a coarse dacitic ground-mass. 

 Fig. 6. — Photomicrograph of the Schistose Dacite, x 21, polarised 



light, showing the hypersthene in process of alteration to 



biotite, and the foliation of the latter. 



