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PROCEEDINGS OF SECTION C. 
•also used facies in determining tlie age of the sands of the Dry Creek 
and Croydon bores to be Older Pliocene. He records 210 molluscan 
species, and has worked out the percentage of living to extinct forms 
as about twenty-seven. He states, however,* * * § that he is “ fully aware 
that the proportion of living species is too low to justify its employ- 
ment as measured by the European standard ; yet in this case the 
percentage principle of classification does not adequately express the 
modern com plexus of the whole fauna.” If facies as applied to the 
mollusca of Tertiary beds is so important in some cases as to make the 
percentage principle as flexible as this, why is facies so often wholly 
neglected, and the percentage system of classification so rigidly 
adopted ? 
Mr. J. Stirling, in his “Notes on a Recent Classification of the 
Older Marine Tertiary Reds of Victoria,”! states that the beds “ show 
a high percentage of forms said to be referable to an Eocene facies/’ 
This remark is very misleading, and is most certainly not the basis 
upon which our beds are classed as Eocene, 
Sir E. McCoy also states in a recent report J that “ the percentage 
of recent mollusca is far higher than in any such recognised Eocene 
sections (London clay, Barton beds, and Paris basin)”; but I have been 
quite unable to find any definite statement of the exact, or even 
approximate, percentage of living forms in any of our Victorian beds 
in Sir E. McCoy’s publications, or in those of the Geological Survey 
or Mining Department of the colony, with the single exception of the 
implied instance above considered. 
In the same report the polyzoa are said fo amply bear out his 
original determination, but it is only very recently § that the more 
definite statement has been made that 12 per cent, of these organisms 
arc living species. There is evidently some mistake here, for Dr. 
MacGillivray, in his monograph, sets down the percentage of recent 
species at 35*6, based upon the whole of the species he has recognised 
from the various beds from which he has hitherto had material. No 
cognisance has, however, been taken of the fact that two distinct beds, 
Eocene and Miocene, occur at Muddy Creek, and on that account we 
are not yet aware whether any appreciable difference is noticeable 
between the polyzoa of these two horizons. He also stated that some 
authorities separate the beds into Oligocene and Miocene, whereas 
others regard them as Eocene ; but the polyzoa, as far as yet examined, 
clearly indicate that the beds from which they have been obtained are 
of one and the same age. 
In the discussion ensuing upon Dr. MacGillivray’s paper, he stated 
that he did not regard the polyzoa as of any importance in determining 
the ages of our Tertiary beds, and that, so far as he was aware, no 
attempt to use these fossils for classification purposes had been made 
in Europe. 
Professor P. M. Duncan, in his papers on our fossil echinodermata, 
evidently experienced the same difficulty in understanding the sub- 
divisions of our Tertiary beds by the Geological Survey of Victoria as 
* Trans. Roy. Soc. S.A., 1890, p. 178. . 
f Prog. Rep. Geo. Surv. Vic., vol. viii., 1894, p. 48. 
X Ann. Rep. Dept, of Mines Vic., 1893, p. 19. 
§ Prog. Rep. Geo. Surv. Vic., vol. viii., 1894, p. 48. 
