106 E, 0. Teale: 



Later field work by Murray (25), Ferguson (26), and 0. A. L. 

 Whitelaw (27), has added a little to the details concerning the dis- 

 tribution and boundaries in a few localities, but no further petro- 

 logical work has been done, nor had any chemical analysis ever l^een 

 made of rocks from the ** Snowy River Porphyries." 



Professor E. W. Skeats (28), in his paper on the Volcanic Rocks 

 of Victoria, gives a summary of Howitt's description of the " Snowy 

 River Porphyries," dealing with their distribution, geological rela- 

 tions and petrological character. Briefly, they form a north and 

 south belt up to about thirty miles in width, and extending south- 

 wards for sixty miles from near the head waters of the Murray, 

 where the highest points rise to over 6000 feet, to the head of Lake 

 Tyers, where they pass under fluviatile and marine Kainozoic de- 

 posits at less than thirty feet above sea level. Some doubt has Ix^en 

 expressed as to the exact age of these rocksw It has been shown clearly 

 that they are pre-Middle Devonian, but there is some uncertainty 

 as to the lowest limits of the series. Mahony and Griflith Taylor 

 (29), in dealing with the geology of the Federal Territory, compare 

 certain quartz-porphyries of that region with the '' Snowy River 

 Series," but they claim that they represent in the Federal area, an 

 Upper Silurian volcanic activity, which continued into the Lower 

 Devonian. In Victoria, the beginning of this important volcanic 

 outburst cannot yet be fixed so certainly, as Upper Ordovician 

 graptolites are the only definite fossils obtained from the older sedi- 

 ments, on which the volcanoes rest unconformably. 



Howitt's petrological examination of this rock was of a prelim- 

 inary nature, and he describes them as quartz-porphyries (in which 

 orthoclase prevails over plagioclase, a point to be referred to again 

 later), felstones (acid lavas), ash and agglomerates. 



General Surface Features. — The physiography of tlie area under 

 consideration will be discussed separately under the section devoted 

 to that purpose. It will only be necessary here to mention a few 

 salient points. 



The southern portion is part of a low coastal plain of soft rocks, 

 rising, as a rule, not more than several hundred feet above sea 

 level. The uppermost beds consist of fluviatile ^rits, sands, gravels 

 and boulder deposits, which, in the south, overlie marine Kainozoic 

 limestones and marls, but further north than about twelve miles 

 from the coa^st, they rest directly on the older rocks. 



The rest of the region forms a I'Ow portion of the Victorian Hi^rh- 

 lands, most of which is below 1000 ffeet in altitude, and its south- 



