Secondary Beds of Northern Australia. 121 



valley of the Burdekin, having a course of some four hundred 

 miles, and then joining a similar valley coming from the 

 south, when the united waters break out of the table-land 

 and escape to the east coast. The Burdekin is fed by tribu- 

 taries coming from each side of the valley ; but the western 

 side is the principal drainage area. 



From the coast to the top of the range the road passes 

 over granite rocks, and beyond this the same rock alternates 

 with bands of Silurians up to the east bank of the Burdekin. 

 The western bank consists of basaltic rock, and the present 

 river-channels is of modern date, worn out on the line of 

 junction between the basalt and the silurians, after the 

 deeper part of the old valley had been covered up by the 

 volcanic rocks. 



Leaving the Burdekin, the road passes over basaltic rock 

 for about one hundred miles, when the auriferous formation 

 near the head of the Cape River crops out. This consists of 

 bands of metamorphosed silurians, from whence specimens 

 might be selected in all stages of the change from a schistose 

 to a granitic character. Beyond this granite again prevails, 

 and then the older rocks are covered up with basalt up to 

 the edge of the Flinders Plains. The road from the range 

 leads down a gorge worn in the volcanic rock, which at its 

 junction with the Flinders River must be over three hundred 

 feet in depth. 



This escarpment forms the western flank of the coast 

 range, and from it extends the country known as the 

 Flinders Plains, to the coast at the Gulf of Carpentaria on 

 the north, and to the M'Kinlay Ranges on the west, the 

 latter being a distance of some two hundred miles. 



This wide valley is nearly level country, with' slight 

 depressions in the neighbourhood of the larger water courses. 

 Where crossed, its main drainage-channel is the Flinders 

 River running to the Gulf, and receiving many tributaries 

 from the west, having their origin in the M'Kinlay Ranges. 

 Some fifteen of these small creeks were struck in travelling 

 across the plains from the Flinders to the Cloncurry, and the 

 latter river joins the Flinders about one hundred miles north 

 of the line travelled over. These water-courses frequently 

 spread out into numerous branches in the level plains, and 

 in some places it is difficult to make out which is the main 

 channel. At the Flinders and Cloncurry rivers, there is a 

 narrow belt of timber on each side of the stream, then green 

 banks from ten to thirty feet deep, and between these a wide 



