230 OREAT SERPENTINE-BELT OF NEW SOUTH WALES, vi., 



is an acid granite, with small aggregates of tourmaline. (See the 

 eastern portion of Section 1, Plate xx.). 



On Yellow Rock Gully, eight miles north of the Namoi River, 

 the Eastern Zone, immediately adjacent to the Serpentine Line, 

 contains two small lenses of limestone with traces of fossils 

 resembling Syrincjopora, and a dendroid Favosltes. These pro- 

 bably belong to the Middle Devonian Series. Between them 

 and Crow Mountain, six miles further to the north, the Eastern 

 Series, immediately adjacent to the Serpentine Line, contains 

 frequent occurrences of a spilitic tuff filled with fragments of 

 limestone, like that which elsewhere represents the Nemingha 

 limestone horizon (1, Pt. v., p. 553). 



East of Crow Mountain, which consists of red jasper, there is 

 a gentle slope leading up on to the New England plateau. The 

 rocks are chiefly indurated claystones and phyllite, with altered 

 tuffs and a large amount of sheared and often vesicular spilite. 

 Near the mountain are several narrow bands of serpentine. At 

 the head of Eumur Creek, five miles east of the mountain, is a 

 lens of limestone, 800 yards long, and 50 yards wide, associated 

 with altered tulF. It is doubtless a continuation of the Middle 

 Devonian (Nemingha ?) limestone of the Mundowey region. The 

 rocks developed east of Woods' Reef, within three miles of the 

 serpentine, are similar to those at Crow Mountain. 



Stonier has recoi-ded the presence of Tertiary gravels, which 

 commence at the head of Back Creek, south-east of Crow Mount- 

 ain, and pass across the Serpentine Line through the low gap 

 south of the mountain (21), and similar gravels occur south of 

 Woods' Reef. These are further discussed below (pp. 240, 275). 



Twenty miles to the north of Woods' Reef, a traverse was 

 made from the serpentine eastward through Gulf Creek. Adja- 

 cent to the serpentine are two small bands of crystalline lime- 

 stone formerly used for flux, of which an analysis has been given 

 (1, Pt. iii., p.712). East of them is a z(5ne of jasper and phyllite 

 with abundant quartz-veins, forming the usual ridge east of the 

 serpentine On the eastern slope of this is the Gulf Creek Mine 

 described by Mr. Carne(30), and consisting of three lodes of 



