BY LEO A. COTTON. 735 



area. The observations are grouped and correlated, as, it is 

 hoj)ed, will best serve as a basis for a genetic discussion later on. 



Geography. 



Tingha is situated about 16 miles south by east from Inverell, 

 and may be reached by coach from that town. Elsmore lies 

 some 12 miles north by east from Tingha, on the Inverell to 

 Glen Innes mail coach route. Most of the tin-bearing country 

 lies between the latitudes fixed by these two towns, though tin 

 has been found in small quantities some miles south of Tingha. 

 The area found to be tin-bearing is represented on the 

 accompanying map, and its extent may be roughly estimated at 

 about 300 square miles. The drainage of the area conforms to 

 two river-systems, the Macintyre and the Gwydir, which form 

 respectively its northern and western boundaries. The Inverell- 

 Armidale road runs along the ridge forming the watershed of 

 these rivers. 



Topography. 



It is necessary under this head to anticipate the section on 

 geology to the extent of stating that the geological units consist 

 of slates and claystones, granites, and basalts. Each of these 

 units give rise to a characteristic topography and vegetation. 



The slates and claystones are much metamorphosed, and resist 

 very strongly the attacks of weathering. Consequently, they 

 stand out as high, rugged ridges, and are scored with steep 

 gullies. They are invariably strongly jointed, and weather into 

 sharp, angular fragments which make travelling difficult. 



The granites, though varied in structure and composition, 

 present a uniform set of topographical characteristics. Huge 

 tors and piles of granite-boulders are common throughout this 

 granite-area. The boulders present a general ellipsoidal appear- 

 ance with their long axes vertical, and are, as a rule, somewhat 

 flattened on the south side. Several very interesting sketches of 

 these are given in "Mines and Mineral Statistics of New South 

 Wales" published by the Department of Mines in 1875. 



