170 THE GEOLOGY OF DUBBO, 



THE GEOLOGY OF DUBBO. 

 By the Rev. J. Milne Curran, F.G.S. 



(Plates 22 and 23.) 



latroduction. — Dnbbo is situated on the verge of the gi'eat alluvial 

 which characterise the interior of New South Wales. A few 

 miles to the north-west, we see, as it were for the last time, the 

 older I'ocks before they are lost, as truly as if they dipped under 

 the sea. The general aspect of the country is level. There are 

 no mountains, and the few hills which diversify the otherwise 

 almost uniform level are simply patches of basalt or of a veiy 

 ferruginous conglomerate which have been able to resist the 

 denuding influences better than the prevailing sandstones. 



The average height above the sea of the country, immediately about 

 Dubbo, may be taken at 900 feet. Although not situated exactly on 

 the plains which extend hence towards the west and north-west, 

 yet the same causes which have been at work to form those plains 

 are very marked in their efi'ects about Dubbo. In other words 

 the present physical features of the country are due more to a 

 filling up process than to the effects of denudation. The pre- 

 cipitous and rugged country about the Upper Macquarie, the 

 chains of basalt capped hills in the Bathurst district, and all the 

 surfaces which form the valley of the river down to Wellington 

 have been carved into their present shapes by the subaerial 

 influences of air, frost, rain and rivers. Near Dubl)o we might 

 draw the line which would show the limit of deposition, denu- 

 dation and deposition being synchronous and co-equal. The 

 basaltic hills referred to have their representatives at Dubbo, 

 but with their summits barely on a level with the surrounding 

 country. 



Frevioics Observers. — Mr. Stutchbury, when in theemployment of 

 the New South Wales Government, visited the coal seams which 



