president's address. 27 



Murrumbidgee after receiving the drainage of this area en- 

 counters the Black Andrew Range, through which it has 

 carved a great gorge at Burrinjuck.* Following the principle 

 already advanced in the case of the Hawkesbury Gorge at 

 Wiseman's Ferry, the Burrinjuck may be cited as evidence 

 that the hill gradually rose against the river. Troughs would 

 be produced by the elevation of folds parallel to the Black 

 Andrew Kange. The Rev. W. B. Clarkef insisted emphati- 

 cally on the folding which has occurred in this ai'ea. He 

 wrote, "The parallelism of the ranges and rivers, including 

 the Shoalhaven, the Cjueanbeyan, the Murrumbidgee, the 

 Coodradigbee, and the Tumut, all of which have a general 

 trend from S. to N., between the parallels of 35 degrees and 

 36 degrees S., is not without a significant cause:'' and again, 

 "The Murrumbidgee runs in the straight course it pursues 

 from above Bullanamang to below Michelago in a synclinal 

 depression." Though at first sight these streams might ap- 

 pear to lie in valleys of erosion guided by choice of softer 

 rock, it is suggested that original fold valleys were here 

 deepened by erosion. 



Apparently unacquainted with the studies of his prede- 

 cessor, Mr. T. G. Taylor, half a century afterwards, came to 

 the same conclusion. He writes, "Indeed the Goodradigbee, 

 Tumut and Adelong Rivers, may all have been determined 

 by folding or faulting in accord with the general north-south 

 trend of the rocks in this area. The sudden bend of the 

 Murrumbidgee to the west, near Yass, probably indicates 

 where the river leaves the uneasy crust of the Monaro High- 

 lands for the comparative solidity of the western plains.'J 



The capture of the head of the Snowy River by the Mur- 

 rumbidgee, described in such admirable detail by Taylor, 



* Siissmilch, Joiini. Roy. 8oc. N.S.W., xliii., 1909, PI. x. 

 t ('laike, " Kesearclies in the Soutlieiii (jloldtieKl.s, 1860," pp. 73 and 81. 



+ Taylor, " Pliysiugvaphy of Federal Territory." Bull, vi., Bureau of 

 Meteorology, 1910, p. 11. 



