34G ORKAT SKKPKN'I'INE BELT OF NKW SOUTH WALKS, vii.. 



sented b}^ a fairly continuous band of pyroclastic rocks, which 

 lies a short distance below the Loomberah limestone. Sills of 

 dolerite do not occur in this, but lie a short distance below it 

 as. for instance, in Portion 61, Loomberah (here the felspar is a 

 labradorite with a marginal zone of oligoclase), and in Portions 

 59, 58, 24, and 35, in which also the felspars are free from albi- 

 tisation. The tuffs, however, are more continuous than the in- 

 trusive rock, and may be traced right through into the Nundle 

 region . 



The Nemingha lied Breccia. — A second igneous zone occurs in 

 the Loomberah District, which is of more distinctive nature and 

 stratigraphical value than the one last noted. It is in close 

 association with the Nemingha limestone, and may be termed 

 the Nemingha Red Breccia, It is especially marked by the 

 presence of a deep red colour. The breccia of which it is com- 

 posed has evidently been subjected to the action of solutions 

 rich in iron, soda, and carbonates, which have introduced much 

 magnetite and htematite into the rock-fragments, and converted 

 their felspars into albite and carbonates. The zone appears first 

 well developed in Portion 58 (Mr. Carter's property), tlie breccia 

 lying along the western side of each band of limestone {see p. 330). 



It occurs again in the western corner of Portion 55 near the 

 Jasper Knob, and traces of it are seen in the fields south of 

 here. It does not form a definite band, however, until Portion 

 32 is reached, and there it is marked by a mass of porphyritic 

 dolerite. From this point, it extends to the south, closely asso- 

 ciated with the limestone, which at first lies on the east side 

 only, but, nearer Black Jack, appears also west of a band of red 

 breccias five hundred yards in width. Half a mile north of 

 Black Jack, the limestone and breccia-zone is thrown nearly half 

 a mile to the east and its width is nearly doubled, but a second 

 fault crossing the northern face of the mountain while moving the 

 centre of the band of breccia about a hundred yards further to 

 the east, causes it to return to a width of approximately three 

 hundred yards. It is here greatly broken, and numerous masses 

 of Nemingha limestone occur in it. The same horizon has been 

 traced across Cope's Creek, and as far as Silver Gully. Here, 



