38 Geological Relations of the 



from the corner of the curve, and the drainage of the 

 Cordillera flows in channels, between north and south ridges, 

 to the united channel. A great part of the district is covered 

 by dense scrubs, and only two main routes through it exist, 

 one of which is described in the Diary of Dr. Leichardt, in 

 ] 847, which I published, with his original chart, in Waugh's 

 Sydney Almanac, in 1860. A copy of this I placed in the 

 hands of Sir Henry Barkly. Since then, the chart has been 

 much improved and altered by subsequent additions. But 

 though some chaining has been done, no final survey has 

 been yet made of the district, and I believe that the 

 country south of the Balonne and west of the Condamine 

 is almost a terra incognita. It is, therefore, not improbable 

 that hereafter some important geological discoveries may be 

 made in that region. . 



The Balonne, which has a southerly trend from its head, 

 about the 149th meridian, turns to the south and is joined 

 by the Cogoon, which traverses the Fitzroy Downs, and rises 

 not far from Mount Abundance, on the west of which 

 Mitchell found his " Belemnite." West of the Cogoon, but 

 coming further from the north, runs the Maranoa River, 

 upon which occurs Mount Sowerby, about forty-five miles 

 north-west of Mount Abundance, and here again, in red 

 ferruginous sandstone, shells, wood, and other fossils were 

 found by Mr. Kennedy. Drift coal was found in a creek 

 near by, at the height of 1,190 feet above the sea. I have 

 made arrangements for the examination of that neighbour- 

 hood, and hope to report on it hereafter. 



Wollumbilla Creek appears to be near the eastern limit of 

 this geological region, and as between it and Mount 

 Abundance fossils of like age have been found, the area, in 

 which the Wollumbilla formation has now been found, may 

 be roughly estimated at 6,500 square miles. It is possible 

 that that whole area is not composed of one set of beds, and 

 tnere is evidence to show this. But at the limits of this 

 area, the fossils, described by Mr. M'Coy below, have been 

 lound. 



The Maranoa has a direct length of 200 miles, and a fall 

 of about five feet per mile ; the Cogoon seventy miles, with 

 a fall of about eight feet per mile ; the Condamine and the 

 Balonne fall at the rate of from' three to four feet per mile, 

 through a course of 300 miles. These data are assumed 

 from calculations made either by the late Rear- Admiral King, 

 from Sir T. L. Mitchell's observations, with the instrument 



