GEOLOGY OF THE GLOUCESTER DISTRICT, N.S.W. 241 



II. The Bar r aba Series. — The thick series of radiolarian 

 mudstooes and tuffs which outcrop on the Gloucester- 

 Copeland road, between the six and seven mile posts, 

 probably belong to this series. They, however, do not 

 make good outcrops, and may possibly be part of the Tam- 

 worth Series. They contain abundant radiolaria, while 

 specimens of drift Lepidodendron are not uncommon. Some 

 of the mudstones outcropping on the railway line between 

 Bulliae and Gloucester may also belong to this series. 



III. The Gold Reefs in the Devonian Strata. — In that 

 part of the district adjacent to the village of Oopeland, the 

 Devonian strata are intersected by a number of auriferous 

 reefs. Those examined by the writer, viz., the Mountain 

 Maid reef and Sawyer's reef, strike approximately east 

 and west, and hade to the south. 



The reefs are lenticular, varying from 6 to 10 inches in 

 thickness, and the walls display well developed slickensides. 

 The ore consists mainly of quartz, with a little pyrites, 

 and with some angular fragments of country-rock embedded 

 in it in places. The reefs are obviously, therefore, true 

 fissure veins deposited along lines of faulting. The gold 

 occurs in irregular shoots which are sometimes very rich, 

 but which are usually short. These shoots pitch to the 

 east. The gold is free, but the reefs also contain a little 

 auriferous pyrites, and more rarely a little galena. Owing 

 to their small size, and the smallness and irregularity of 

 the shoots, these reefs have not proved very remunerative 

 and not much work is at present being done on them. 



B. The Carboniferous System. 

 The Carboniferous strata occur in the form of a large 

 syncline striking practically due north and south. They 

 are divisible into a lower series of marine origin — the 

 Burindi Series — and an upper series of terrestrial origin — 

 the Kuttung Series. The details of the Carboniferous 



P— December 7, 1921. 



