54 Proceedings of the Royal Society of Victoria. 



Source of the Material. 



The materials of the pebbles require for their supply a land 

 surface of sedimentary rocks already invaded and altered by 

 igneous rocks and with volcanic rocks also exposed. The altered 

 sedimentary rocks are represented by the quartzite, poi'cellanite 

 and lydianite ; the igneous by the quartz porphyry, greisen, a 

 peculiar line graphic granite, and a vascular fragment. Vein 

 quartz also occurs. 



The land area of Heathcotian rocks, as recently described by 

 Dr. Gregory^ may have provided these materials. The position of 

 the beds is in the gap existing in Upper Ordovician times in the 

 ridge southward from Lancefield ranges. 



Age op the Conglomerates. 



In a former paper referring to these conglomerates, I stated 

 that their Ordovician age was uncertain. 



The Quarter-sheet appears to show all the palaeozoic rock in 

 7. S.E. as "Lower Silurian" a number of fossils being recorded 

 at the north-west corner of the sheet. As the whole of the 

 bedrock exposed along the Saltwater in 2. S.W. is mapped as 

 "Upper Silurian" the question of the actual contact appears to 

 be avoided. There is a fossil locality Ba60 marked on the Deep 

 Creek (close to locality 5) of which I have found no mention in 

 published reports, but it would support, no doubt, the extension of 

 the "Lower Silurian " colouring to the Deep Creek, which is 

 near the east side of the sheet. On a copy of 7 S.E., at the 

 Melbourne Public Library, I found that the Lower Silurian 

 colouring stops a short distance before the edge of the Quarter- 

 sheet (at the line J on the locality map), a small space being left 

 uncoloured. In all other copies I remember to have seen the 

 "Lower Silurian " colouring extends to the edge of the sheet. 



On visiting the locality, this part of the river channel looked 

 at first very unpromising for rock exposures, alluvial material 

 being abundant ; but the river being low, a small outcrop of rock 

 was found exposed on the right bank close to the water within 

 the area uncoloured on the Public Library map. A rough 

 observation of strike and dip gave strike about N. 30° W. dip 



1 Proc. Royal Society Vic, vol. xv., pt. ii., n.a. 



