704 NOTE ON DEVONIAN AND CARBONIFEROUS FORMATIONS, 



The section is not detailed on account of the difficulty of obtain- 

 ing outcrops, and also the short time at our disposal. It is intended 

 to illustrate, in a general way, the lithologieal character and struc- 

 tural features of the strata. 



From Tamworth to within two miles of Carroll Gap (see Fig. 2), 

 the rocks consist of interbedded tuffs and cherts, with one charac- 

 teristic band of limestone. The tuffs and cherts exhibit consider- 

 able variation in their development. In some places, the tuffs 

 appear massive, with very little chert, and in others (particularly 

 the cutting near the 10-mile peg from Tamworth) there is very little 

 associated tuff with the chert. Occasionally, tuffs and cherts are 

 closely interstratified, as at a point about SVo miles from Tam- 

 worth, where six bands of each were observed in a thickness of 

 about 20 feet of strata. The bed of limestone referred to, is about 

 10 feet thick. It is a black, fine-grained rock, characterised by the 

 presence of small, lath-shaped crystals about 4 mm. by 0-5 mm. 

 Examination under the microscope and treatment with HCl show 

 that they are composed of caleite, but their distribution suggests 

 that they are replacements of some original structure. This was 

 observed in three distinct places, viz., 5-2, 107, and 214 miles from 

 Tamworth. 



The plotting of the dips on the map showed that we were dealing 

 with a series of anticlines and synclines, and the strikes indicated 

 that these were tilted. From the information obtained, we calcu- 

 lated that the axis of tilt is about N.3°W., and the amount of the 

 tilt from 6-7° towards the north. Reference to the section (Fig. 

 2) will show how these folds harmonise with the anticline east of 

 Tamworth. 



The presence of quartz-reefs in the reading cutting 10 miles 

 from Tamworth, observed by Messrs. Harrison and Aurousseau, 

 renders it not unlikely that the Moonbi granite-series underlies this 

 portion of the section. 



The most westerly observation of the dip of this series was at a 

 point about two miles east of Carroll Gap. Between this point and 

 Carroll Gap itself, outcrops are obscured by recent alluvial, and at 

 the latter place, there is a bold outcrop of limestone dipping to the 



