Falaeozoic Geology of Victoria. 113 



Xiady Torr Creek. These occurrences are distinct from the iron 

 deposits in the porphyry, to be referred to later, the latter consist- 

 ing largely of hematite, while the former appears to be the type of 

 gossany cappings, which may develop into sulphides at a depth. 

 No work, however, has been done with a vieAv to testing these 

 -deposits. 



Another Ordovician area still remains to be referred to. It forms 

 part of a large region whicli extends to the Snowy River, and 

 beyond into Croajingolong. Along its western boundary it is in 

 contact with tlie Snowy River Porphyries. The line of junction 

 has not been accurately traced, but it bears in a general N.N.E. 

 direction. My own explorations here have been very limited, and 

 were confined principally to the vicinity of the Orbost bridle tra^k, 

 and to a rapid reconnaisance along the now disused track to Bete 

 Bolong, on the Snowy River. Some obscure graptolites were found 

 close to the western boundary, with the porphyry, and are probably 

 Upper Ordovician. The general strike as far as observed lies be- 

 tween N. and N.E., and it, is worthy of note that this direction is 

 characteristic of nearly all the features in this region as a whole. 

 It is not confined merely to the strike of the strata. The belts of 

 Ordovician, of porphyry and Middle Devonian limestone, also the 

 longer axes of many of the granite batholiths. the major faults, and 

 the trend of the various ore deposits, all conform approximately in 

 this direction. It is in contrast to a north-westerly trend, which 

 is a marked feature over a wide area to the west, and it would 

 appear to be a continuation of the important trend lines of this 

 direction so well developed in New South Wales. 



The Snowy River Porphyry Series. — The distribution of the 

 rocks of the series within the area here considered is shown on the 

 map in which the characteristic! N. and S. to N.N.E. trend is well 

 shown. 



Porphyritic rocks of an acid type and general pinkish to brown 

 colour prevail on the rocky ridges, the highest point in the region 

 culminating in Mt., Tara, about 1930 feet in height. 



These rocks being of a relatively hard and resistant nature, natu- 

 rally form exposures, while large intervening areas are so masked 

 ■with soil that little idea can be obtained as to the nature of the un- 

 derlying rock. The spoil heaps, however, of some of the now 

 abandoned mining shafts and other excavations frequently suffsfest 

 some types, sliowang considerable variation from the acid por- 

 phyries, and allied rocks of the ridges, and the sections in Boggy 



