70 YHE VICLORIAN NATURALIST 
Mine was sunk, I may say that it is a Basalt-Vitrophyr of the sub- 
division Tachylite, with included fragments of more crystalline lavas 
of the Basalt group. 
*Zirkel, Mikroscopische Beschaffenheit der Mineralienund Gosteine, 
p. 484. ~ ; ; 
+Rosenbusch, Mikroskopische Physiographie der petrographisch 
wichtigen Mineralien p. 137. : ; 
tRosenbusch, Mikroskopische Physiographie der massigen Gesteine, 
p. 445. 
GEOLOGICAL SKETCH OF SOUTH-WESTERN 
VICTORIA. 
By Joun Dennant, 
INTRODUCTION. 
Tus following outline of the geology of the south-western portion 
of Victoria, is the result of observations made while travelling 
through it for business purposes on various occasions. 
The region described lies between these boundaries :—West, the 
South Australian border ; East, Norton’s Creek, Serra Range, and 
a line drawn from Mount Abrupt to the Eumeralla mouth ; South, 
the coast line; and North, the Mallee fringe. 
A few preliminary notes are made on its physical geography. 
The only mountain ranges are on the East, forming a part of the 
Grampians, and divided into the Dundas, Victoria, Serra, and Black 
ranges. A great number of volcanic hills of low elevation are found 
in the South, the principal being Napier, Rouse, Eccles, Clay, and 
Kckersley. 
The river Glenelg rises on the western slopes of the Serra, and 
runs northwards and westwards between the Victoria and Black 
ranges, thence on past Balmoral and Harrow, when it bends to the 
South, and finally, after an exceedingly tortuous course, flows into 
the Southern Ocean, near the South Australian boundary. The 
scenery along its banks is of the most varied character, every 
geological formation in the district being cut through by it on its 
way to the sea. 
Rising in sandstone country, it passes through granite at Harrow 
and Dergholm, slates at Roseneath, mesozoic strata at Casterton, 
pleistocene shell deposits at Pieracle, and miocene limestone at its 
mouth. The Wannon, whick rises in the same range, but on the 
opposite or eastern slope, flows South and West around Mounts 
Abrupt, Sturgeon, and Victoria, past Dunkeld and Cavendish, and 
on through rolling downs of extreme fertility to its junction with the 
Glenelg at Sandford. The other principal tributaries of the 
