feV W. N. BEMSON. 355 



acter of sediment. In this series occurs the zone of the Scrub 

 Mountain Conglomerate, which, commencing in the south-west 

 of Loomberah Parish, may be traced to beyond Nundle. There 

 is at present no evidence to show the change in geographic con- 

 dition which led to the development of this formation, but the 

 suggestion has been made above(p.341) that it represents a con- 

 glomerate laid down by a sea transgressing over a region which 

 has been upwarped during the eruption of the immense masses 

 of pyroclastic material forming the Baldwin Agglomerates, which 

 extend intermittently from Tamwoj-th to Bingara. If this be so, 

 the Scrub Mountain Conglomerate is approximately coeval with 

 that outbreak. 



No angular or lithological unconformity, however, has been 

 recognised between the mudstones above and below that con- 

 glomerate. The mudstones above this region (which, if the pre- 

 sumed stratigraphic position of the conglomerate is correct, 

 belong to the Barraba Series) are exactly like those below. They 

 contain the Pyramid Hill tuffs, the centre of eruption of which 

 was near the Pyramid Hill Range, for they die out to the north- 

 west and also to the south-east, as is indicated by the topograjDhy 

 of the regions beyond the area mapped. Higher beds than this 

 have not been tiaced in this region. 



'I'lic fSerpenliiie^^ etc. 

 The band of serpentine in the south-eastern c(n-ner of the map 

 of the Tam worth district, continues for nearly a mile till, near the 

 iiuiin road in Portion 83, Nemingha (behind Mr. White's resi- 

 dence), it is sharply cut off by a small fault, which lias displaced 

 the eastern series a distance of about 100 yards to the north-west. 

 The serpentines of the above band ai-e of varying width, and 

 largely schistose, and do not show an^^ relief. A notew^orthy 

 feature is the occurrence in the serpentine, in Portion 105, of a 

 very coarse pegmatitic mass of albite and quartz, which has 

 been shattered and seamed with further veins of quartz. 

 Similar albitic veins occur elsewhere in the serpentine (4, pp.69 1- 

 2). South of the above-mentioned fault, no continuous zone 

 of serpentine is met with. A small lenticle, about 60 yards in 



