83 



of Barrow Range, as isolated hills of graniilite, whicli is distinctly 

 stratified with a low angle of dip towards south. I consider this 

 granulite as a part of the formation of the Townsend Ridges, of 

 which it may represent a lower stratum. Pieces of a scaly 

 quartzite, containing small lamina; of white mica were picked up 

 at old " wurleys " and camping places of the blacks, who have 

 apparently used them as grinding-stones for seeds, and, although 

 not seen in situ, yet there is presumptive evidence that this very 

 distinctive rock occurs within the geographic limits of the tribe. 

 A specimen of a similar quartzite was collected by Mr. Leech at 

 the Sutherland Range, where it, as he informed me, occurs in low 

 ridges, with a southerly escarpment. 



The width of this Paheozoic belt, of which quartzite seems to 

 be the main component, varies probably very much, but from the 

 evidence already adduced, it extends between latitudes 27° 35' 

 and 28° 30', at least 100 miles towards south, whilst at the 

 Townsend Ridges it does not exceed 30 miles, though it is liero 

 abundantly covered with Tertiary deposits. 



B. Ekuptive Rocks. 



1. Plutonic Rocks. — Granite of a truly eruptive character is the 

 most prevalent member of this class. At all places of its occurrence 

 it presents on the surface a spheroid or ellipsoid outline, and ex- 

 hibits internally a concentric structure. Large cuboid al masses of 

 it are abundantly scattered over the granite hills, their shape being 

 the result of cleavage in three directions almost perpendicular to 

 each other. The Everard and Birksgate Ranges consist almost 

 entirely of eruptive granite, as also the main mass of Barrow 

 Range. However, outcrops of granite were observed which 

 possessed a somewhat metamorphic character ; Ijut these were 

 generally as outliers of the main ranges, and very probably belong 

 to the schistose series overlying the eruptive granite. 



The eruptive granite is generally poor or destitute of mica, its 

 substitute being either hornblende or epidote ; felspar crystals 

 are prevalent, they are generally colourless or milky wliite, but 

 are of a yellowish red when found on the surface. 



Diorite. — As already mentioned, p. 77, the granite is very 

 frequently intersected by dioritic dykes ; they prevail in the 

 country between Mount Gosse and Barrow Range, and in 

 Cavenagh Range the hornblendic eruptive rooks reach their 

 maximum of development, as these hills are entirely composed of 

 them. In the Cavenagh Range there occurs a diorite which has 

 a stratified structure, not only petrographic Isut also architec- 

 tonic, but 

 eruptive, 

 crystals to a kind of macro-iluctuation structure. The dioritic 



in spite of this I do not hesitate to pronounce it 

 as I attribute the parallel position of the pyroxene 



