On Certain Conglomerates near Sydenham. 51 



expected from material like that at locality No. 1, altered at the 

 granite contact. The general dip here is easterly at about 60°. 



At localities 5 and 6 I did not see the conglomerate. 



At locality 7, conglomerate is seen on the right bank of the 

 Saltwater north of Keilor township. The pebbles, to about 10 

 inches in size, are mainly quartz and quartzite, similar to those at 

 No. 1, in a matrix mostly sandy, but I did not notice any pebbly 

 mudstones. The northerly extension marked on the quarter 

 sheet is mostly under an alluvial fiat. About the southern end 

 also little rock is exposed. At the point where they were 

 observed the dip is about 50° westerly and the strike east of 

 north. The thickness exposed is about 10 feet. The beds 

 immediately below are mudstones without pebbles and above 

 sandstone without pebbles and again a thin conglomerate bed. 



Glacial Origin of the Pebbly Beds. 



The manner of occurence and distribution of the pebbles 

 through the mudstones suggests at once a glacial transport. 

 The pebbles are of various sizes and in various positions and are 

 embedded in and scattered through a matrix which, even when 

 sandy, would have been completely removed by any current compe- 

 tent to move the pebbles. Only exceptionally are the pebbles so 

 crowded that fine material could have lodged among them and 

 this crowding is only in patches. The general aspect, expect as 

 to inclination, is very similar to parts of the glacial deposits of 

 Bacchus Marsh and elsewhere. They agree also very closely 

 with the description recently given by Mr. Howchin' of certain 

 supposed Cambrian glacial beds near Adelaide, only that here 

 the pebbles do not reach anything near the same dimensions. 



Glaciated pebbles and some striated occur, associated indeed 

 with many rounded ones, and an examination of the matrix in the 

 lower pebbly mudstones at locality 1 shows that it is clear and 

 sharp, rather abraded than weathered material. Some of the 

 pebbles show crystals of pyrite ground down but not decomposed. 

 While no other explanation except glacial transport seems 

 practicable for the general characters of the deposit, the relations 

 to the beds above and below preclude any idea of accumulation 



1 Trans. Royal Society S.A., vol. xxv., pt. i., 1901. 



