Geology of Mount Macedon. 199 



Aegerine is abundant in small angular grains and prisms, 

 which are crowded round the anorthoclase phenocrysts. The 

 riebeckite is in larger crystals than in the rock of the Camel's 

 Hump. 



Nosean, in corroded crystals and biotite, also occur, though 

 sparingly ; the crystals of the latter are fringed with aegerine 

 prisms. 



d. The Andesites. 



On the plains to the north and north-west of Mount Macedon 

 are occasional exposures of weathered rock containing numerous 

 black specks in an earthy grey base. The best exposure is in a 

 small quarry on a hillock in allotment No. 84 in the north- 

 eastern corner of Woodend. The rock is included on the Geo- 

 logical Survey Map as a member of the Cainozoic basalts. As, 

 however, the rock (No. 35) contains anorthoclase, some altered 

 nosean and altered olivine, it is a member of the Macedon series 

 and not of the later basalts. I have not yet succeeded in 

 getting fresh specimens of this rock, and postpone a fuller 

 account of it until better material is available. 



e. Agglomerates and Ashes. 



Exposures of pyroclastic rocks are rare on Mount Macedon. 

 Denudation has probably removed most of them, and what 

 remain now occur in depressions between the more resisting 

 dykes and lavas. 



The best example of agglomerates that I have yet found 

 occurs at Upper Macedon on the i-oadside leading from the lodge 

 at Government Cottage to Mr. Justice Hood's house near the 

 State Nursery. The best section is at the height of about 400 

 feet above the Turritable Creek and a little below some land 

 that belonged to the late Sir F. McCoy. Here occurs a band of 

 agglomerates with blocks of the geburite-dacites up to 4 feet in 

 diameter included in fine ash. Further up the road is an 

 exposure of volcanic ash traversed by a ten-foot dyke of geburite- 

 dacite. 



Well developed tuffs occur in other parts of the Macedon 

 range, as i.e., at Cherokee. 



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