254 GREAT SERPENTINE-BELT OF NEW SOUTH WALES, vi., 



the fault-plane (Text-fig. 4). Various other faults are to be 

 noted along the creek. Some attempt at arriving at their ap- 

 proximate throw may hereafter be made, by mapping the out- 

 crop of a particularly thick, white, tuflfaceous band full of frag- 

 ments of mudstone, which occurs at various points, and, in par- 

 ticular, causes a small waterfall a couple of miles east of the 

 Borah homestead. All this series of Barraba mudstone, etc., 

 dips, more or less, to the E.S.E., and cannot be far above the 

 Baldwin agglomerates. North of the creek, the Black Mountain 

 group of hills rises, a succession of eastward-inclined dip-slopes, 

 and westward-facing fault-scarps (as shown in Text-figs. 5 and 6), 



mm 



^ w i% Hilc^ 



Proboble Profile dlon^AB dtfrfng Tertiary Volcanic ?enod 



Text-fig. 6. 

 Profiles across the Black Mountain Range (Present and Tertiary). 



formed of agglomerate rising from under the mudstone; and 

 nearly every fault-scarp has been traced down to a well-marked 

 fault, seen where it crosses Borah Creek. The throw of these 

 faults may thus be determined roughly by the heights of the 

 various fault-scarps, and, on this reckoning, they vary from 300 

 to 1,000 feet, with the greatest western fault approaching 2,000 

 feet. This western fault determines the scarp of Black Mountain. 

 These faults thus stand up in the Black Mountain Region as 



