50 
Geology and Physical Geography: 
rising abruptly from the level Tertiary country which surrounds 
them ; and it appears likely that the Upper Palaeozoic rocks 
may underlie a large extent of the Tertiary tract to the north- 
west. 
The general physical features of the ranges indicate, beyond a 
doubt, that the Upper Palteozoic rocks which compose them are 
but vestiges of a once more extensively developed formation, and 
that to long-coutinued powerful denuding action is due the re- 
moval of the major portion of the series. 
The eastern Upper Palaeozoic area has only been examined at 
its northern and southern portions, near Mansfield, and in Gipps- 
land, respectively. There appears little doubt as to the rocks of 
the series extending continuously between the two localities and 
constituting a portion of the Main Divide, of whiclUa proper 
geological examination has not yet been made. Viewed as a 
whole, this area is in the form of a wide strip or belt of about 
100 miles in length, north-west and south-east, and averaging 20 
miles in width. The general south-western boundaries of this 
Upper Palaeozoic tract are the Macalister River, and its western 
tributary, the Barkly River, on the southern or Gippsland fall of 
the Main Divide, and a line crossing oblicpiely the upper portions 
and including the heads of the Jamieson, llowqua, and Delatito 
Rivers, eastern tributaries of the Goulburn, on the northern slope 
towards the Murray. The north-western and northern boundary 
is formed by the steep Silurian and granite spurs of the Strath- 
bo°-ie Ranges, and the Blue Range, near Barjarg. The north- 
eastern limit on the fall towards the Murray is approximately a 
line from the Blue Range between the Broken River and the King 
River, to near the head of the latter at the Main Divide, and 
thence on the Gippsland side, a line to the west of, and roughly 
parallel with, the Wonnongatta or Mitchell River to Maximilian 
Creek, where the boundary line turns eastward and then north- 
ward to Tabberabbera. The rocks of the belt here extend east- 
ward of the Mitchell, and occupy portion of the country on that 
side from Tabberabbera to near Bairnsdale. The southern 
boundary is formed by the low-lying Tertiary deposits which flank 
the Upper Palaeozoic rocks along an irregular line from the 
Macalister River at Glenmaggie to tho Mitchell River at Iguana 
Creek. 
The Iguana Creek beds are the typical rocks of that group of 
the Upper Paheozoic division, which has been classed, on good 
evidence, as Upper Devonian, and they are comprised in that 
portion of the great Upper Palaeozoic area which extends eastward 
from Freestone Creek, a branch of the Avon River. The northern 
boundary of this particular portiou is a line skirting Maximilian 
