m E. 0, Teale: 



therefore, that the* diabases and cherts of the Howqiia belong to the 

 Heathcotian series, and must be regarded as Cambrian. Whether 

 also some of tlie adjoining sediments are to be included in this 

 series must at present be left an open question. 



6. — The Upper Palaeozoic Rocks. 



Ihe present investigation Avas principally concerned with the 

 .relationships of the older rocks, but some of the later geology is 

 not without interest, and as rocks of this age are found in the 

 northern portion of the area under consideration, where they come 

 into contact with the diabase, a little time "was devoted to roughly 

 demarking their boundaries and noting their main features. The 

 rocks of this series fall into the following groups : — 



A. — Devonian. 



1. Dacite, porphyry, 



2. Granodiorite. 



3. Diorite. 



B. — The Lower Carboniferous. 



1. Basal conglomerates. 



2. Rhyolite. 



3. Conglomerates. 



4. Sandstones. 



5. Purple shales 



1. Dacite Porjjhyry. — This rock covers a considerable tract of 

 -^country between Mount Timbertop and the Howqua, and extends 

 -easterly towards the Buller Creek, where it gives place to Lower 

 Palaeozoic strata. It is also found to the north outside the region 

 of this map on the fall towards Merrijig. Rock of this nature is 

 widely distributed in the King River Valley, as indicated by 

 Kitson.l2 In both localities it underlies the basal conglomerates 

 of the Low^er Carboniferous beds, in which pebbles of the porphyry 

 are not uncommon. In the Howqua area this feature was noted in 

 the Timbertop conglomerates. Professor Skeats^ has referred to the 

 King River porphyry as related to. the Dacites. In hand specimens 

 the rock has a general dark colour, on account of a dark, fine- 

 grained base. It inclines to red, where oxidized and weathered. 

 Phenocrysts of felspar and quartz are abundant, the former pre- 

 dominating, and show up on the dark base, imparting a typical 

 porphyritic appearance. Garnets are frequently recognizable. 

 Under the microscope in thin sections chemical alteration in all 

 the specimens examined has proceeded too far for satisfactory 

 . determination. 



