106 E. 0. Teale: 



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

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

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

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

 made of rocks from the " Snow}' River Porphyries." 



Profesisor E. W. Skeats (28), in his paiper 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- 

 posita at less than thirty feet above sea level. Some doubt has V;een 

 expressed as to the exact age of these rocks. It has l>een shown clearly 

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

 as to the lowest limits of the series. Mahony and Griffith 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 claini 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 dehnite fossils obtained from the older sedi- 

 ments, on which the volcanoes rest unconformably. 



Howitt's petrological examination of this roc-k was of a prelim- 

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

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

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



General Surface Feofiires. — The physiography fif 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 roc-ks, 

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

 level. The uppermost beds consist of fluviatile grits, sands, gravels 

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

 limestones and marls, but further north than about tAvelve miles 

 from the coast, thev rest directly on the older rocks. 



The rest of tlie region forms a low portion of the Victorian Hirrli- 

 lands, mo.st of Avhich is below 1000 feet in altitude, and its soutli- 



