BY T. GRIFFITH TAYLOR. 



343 



steep quartzite ridges, about 300 feet high. These ridges are 

 covered with a loose talus which is continually dropping into the 



L. Scales 



I" * 





Fig. 6. — Section A B (see fig. 4) across Lake Bathurst, 

 showing the gravel-dam across the outlet and the talus 

 occupying the Mulwaree Valley. 



creek. In the railway cuttings 30 feet or more of this talus 

 (mingled with soil) are evident. 



The explanation of the lake-origin which I venture to put 

 forward is intimately connected with this abundance of talus in 

 the narrow valley of the Mulwaree. 



ChamSPonds MulwcreaR. LoKj^deef^C 



SOUTH Toraao , Grovel ""^ Robb.Ms. Gran.reRT 



Fig. 7. — Sketch view of Lake Bathurst from the top of the Trig. Station 

 on the eastern shore. The black area indicates the extent of water in 

 February, 1907. j jWhen filled, the Lake covers the whole fiat expanse. 



ii. Origin of Lake Bathurst. 



In earlier geological periods, possibly when a somewhat greater 



rainfall obtained in New South Wales, the Mulwaree Creek 



received a pair of tributaries from the east. One of these drained 



the valley now occupied by the Bonnie Doon Lagoon (N.E.), and 



