34 



bluish tinge, while the latter are reddish, the depth of the tint 

 depending upon the degree of oxidation of the iron they contain. 

 Very fine and perfect shells are often found amongst the bluish- 

 coloured clays, especially large volutes and cowries. The bands 

 are horizontal, and though they no doubt indicate some slight 

 difference in the deposition of the sediments, similar shells occur 

 both in the blue clays and the red calcareous layers. It is true 

 that some of the bands contain more fossils than others, but still 

 shells can be obtained in a greater or less quantity in any part of 

 the strata. 



I have hitherto spoken of tlie fossiliferous strata of the Muddy 

 and Grange Creeks as a whole, without indicating definitely the 

 distinction as to age which undoubtedly exists among them. So 

 far as the Muddy Creek itself is concerned, all the beds known 

 consist of the clayey and calcareous layers already noticed, but 

 in the Grange Burn, fossiliferous strata of a different character 

 appear, which have not, I think, been referred to by any previous 

 geological writer. They form a rather friable rock, composed 

 mainly of bryozoan remains, with spines of echini, and occasional 

 shells, chiefly pectens, scattered through it. In outward appear- 

 ance, it resembles almost exactly the strata on the Crawford 

 River, about half way between Muddy Creek and the south coast 

 of Victoria. Somewhat similar strata are also found at Apsley, 

 on the western boundary of Victoria, and also at Narracoorte in 

 South Australia. Those at the last-named place are described by 

 Professor Tate under the name of " polyzoal rock," which in his 

 classification of the Australian Tertiaries he has placed as ante- 

 cedent in age to the Muddy Creek shell beds. In one place only 

 have I seen the strata in close proximity, and there the polyzoal 

 rock appeared to underlie the shell beds. As, however, I was un- 

 able to trace their actual contact, I am not prepared to speak 

 definitely on the point. As said before, this rock is nowhere 

 visible in the Muddy Creek, but it abounds in the Grange Burn, 

 not only above, but also for a long way below its junction with 

 Muddy Creek. The identifiable shells in it are few, and these 

 even are with difiiculty extracted whole, so that its thorough 

 examination will be a work of time. As my own labours, so far, 

 have been almost entirely restricted to the shell-beds, I can do 

 little more at present than direct attention to this interesting 

 formation. 



*■*' As is well known, geologists are not entirely in accord concern- 

 ing the relative ages of the various tertiary strata of Victoria, 

 South Australia, and Tasmania. Professor Duncan, judging from 

 the evidence of the corals and echinodermata, ad^dses that they 

 should all be called cainozoic simply, without attempting further 

 subdivision. The mollusca, however, tell a much more certain 



