BY U. I. JENSEN. 77 



This, as well as breccia, u)ay also be found on all the spurs from 

 the main plug. In the immediate vicinity of the mountain occur 

 several smaller knobs, which clearly represent remnants of flows 

 from the top of Mt. Flinders, which have been isolated by 

 streams undermining them by working into the underlying 

 breccias. As the map shows (plan fig. 2), the Flinders Peak is 

 surrounded by numerous smaller mounts, such as Ivory's Knob, 

 Mt. Goolman, Mt. Blaine, Stafford's Knob, Green Knob, 

 Mt. Elliott and Dwj^er's Knob. Each of these peaks was an 

 independent focus of eruption. 



Ivory's Knob, as the photograph shows, (PI. v. fig.l) is a rugged 

 pinnacle. On examination it was found to consist of breccia made 

 up of fragments of trachyte, sandstone, chert, ikc, cemented firmly 

 by dykes and stockworks of trachyte-lava which had been injected 

 into the breccia. Rhyolitic trachytes must have flowed from the 

 crater of this volcano, and a remnant of a breccia-sheet, capped 

 with a flow of spherulitic obsidian, occurs in Kelly's paddock, 

 Selection 218, Parish of Goolnian. 



Stafford's Knob is simply a plug of rhyolitic trachyte. A little 

 tuff' occurs near its base. 



Dwyer's Knob I did not get to, but its structure appears 

 identical with that of Stafford's Knob. 



Mt. Goolman I did not go to, but it appears similar to and 

 intermediate in structure between Mt. Flinders and Mt. Blaine. 



All the foregoing have a poor grey soil and wretched forest 

 vegetation. 



Mt. Blaine is largely covered with scrub. This is due to the 

 fact that this mountain is mainly composed of breccia, covered 

 with flows of amygdaloidal andesite. The core is, however, 

 trachytic. The andesite and quartz-dacite are merely a basic 

 phase of the trachyte, and I could find no evidence to show 

 whether they were erupted early or later than the true trachyte. 

 The soil of Mt Blaine is brownish, and Pine {Callitris 1) 

 is a characteristic timber. 



rhe Green Mountain has a similar conical appearance and 

 brown soil; the vegetation on it is, however, less luxuriant; and, 



