40 



brown sandstone, which breaks with a sharp cutting edge. In 

 solution of potash it becomes friable after long digestion. This 

 place is known as Algebuckinna goldfield, and was first discovered 

 during the telegraph construction, but the discovery was not dis- 

 closed to the public till about two years ago. The actual channel 

 of the river is filled with a drift of alluvium about 18 feet deep 

 where deepest sinkings have been made, but the locality being 

 one of those few places where waterholes occur, the influx of 

 water prevents full exploration. The gold of this recent alluvium 

 is apparently derived from the coarse gravel stratum overlying 

 the kaolin, as gold is found in it, and the richest finds have 

 been made in the talus immediately under it. The gold is very 

 pure, and brought £4 per ounce at the Melbourne Mint. In appear- 

 ance it is sharp, and the presence of crystals of black ironstone 

 embraced among its projecting parts proves conclusively that it 

 has not travelled far. About three miles up stream is the Ocken- 

 don Creek, which junctions here over gneissoid schists, among 

 which are quartz leaders carrying pyrites ; and possibly it is from 

 this locality that the gold has been derived, although 1 could not 

 detect gold in the quartz T examined. Ten miles north-west of 

 Algebuckinna is the 



5. Mount Duttox Raxge, which lies about ten miles north- 

 west of Algebuckinna, I did not visit ; but as our route passed 

 within two miles of its northern end, I was enabled to distin- 

 guish a succession of beds in appearance like tliose of the Denison 

 quartzites and slates. 



This was the last exposure of metamorphic rocks for the next 

 350 miles, and the conclusions warranted from the examination 

 of their series are the following : — 



1. They are probably outlying portions of the Flinders Range, 

 as their rocks agree in strike, sequence, and mineral comiDosition 

 with that portion nearest the plains. 



2. They are probably a chain of archjvan islands which occupied 

 a shallow sea, as evidenced by the conglomerate beds or breccias, 

 the thick beds of cjuartzites, and continuous bands of limestone, 

 in which schistose fragments are imbedded (though only percep- 

 tible when weathered). 



3. After deposition of the schists, granitic eruptions raised the 

 beds into ridges running nearly north and south. 



4. Great erosion took place before the second period of erup- 

 tive rocks were intruded, and their action faulted, dislocated and 

 greatly contorted the whole system ; and as the mineral deposits 

 are always in their vicinity, they were probably the mineralising 

 agents of the system. 



5. After another long period of erosion, during which the 

 ranges received in great measure their present contour, a period 



