BY W. N. BENSON. 369 



altered by the ferruginous and albitic solutions which traversed 

 the Neming-ha Red Breccia, occur in fragmenta by the limestone in 

 Portion 58. Specimen No. 1116 is a good example. of these. It has 

 a ijub-variolitic to pilotaxitic base, consisting of small laths of acid 

 plagioclase, from which grow-out skeletal felspars or sub-radiating 

 microlites, with finely divided interstitial magnetite, together with 

 larger well-formed magnetite crystals, interstitial quartz, and a 

 very little chlorite. Here and there are irregular areas of calcite. 

 The large phenocrysts of felspar are entirely replaced by albite, 

 dotted with calcite. The trace of the original zoning is very 

 obvious. 



A peculiar type of porphyrite occurs interstratified in the 

 agglomerates between Black Jack and Wallaby Mountain. It is a 

 dense fine-grained, black rock (No. 1435) with phenocrj-sts of 

 fresh augite, usually singly twinned, and large crystals of plagio- 

 clase which are extremely full of inclusions of chlorite, apparently 

 replacing augite-grains, or portions of glassy groundmass, con- 

 taining skeleton-crystals of ilmenite. The groundmass of the rock 

 luis a basaltic texture more like that of some lamprophyres than of 

 spilites. It consists of long prisms of augite and of plagioclase 

 with .skeleton-ilmenite, together wdth a considerable amount of 

 platey chlorite. 



Variolite is represented by a single example (No. 1405). It 

 occurs in the Peel River Company's Estate half a mile to the south- 

 west of the soutliern corner of Portions 31 and 37 (Loomberah). 

 It is a dark green, apbanitic rock with a very poorly developed 

 perlitic fracture. IMicroscopically, it proves to be an extremely 

 finely crystalline rock, composed of sub-radiating sheafs of minute 

 felsiDar-microlites, with fine grains of magnetite arranged among 

 them. There are a few small phenocrysts of albite and augite. 



Th e Ke ra toph i/res. 

 The keratophyres may be grouped into five main divisions. i.The 

 pyroxenic keratophyre. ii.The keratophyre proper. iii.The mag- 

 netite-keratophyre. iv.The nodular siliceous keratoph\Te. v.The 

 keratophyre-breccia. These pa.ss into one another. 



