178 PROCERDINGS GF SECTION C, 
in many cases, on the accuracy with w hich we can assert 
that certain beds are, not merely homoiaziaily, but actually 
older than certain others separated from tbem, it may | 
half the circumference of the globe. 
We aro yet far from: this ultimate goal, and even the 
homotaxy of our beds cannot be said to be settled beyond 
dispute. 
Many attempts have been made to ht the Tertiaries of 
Southern Australia into the British Procrustean sub 
divisions, and I do not know that the results are any more 
satisfactory to. the strata than they were to the guests of 
VPre-~ustes himself. 
Two distinct methods of arri 1g at a result have been 
employed, though one of them is somewhat disguised by 
medificaticns. ‘The one is by direct comparison with Euro- 
pean strata, and the other is by the application of Lyell’s 
method—-the determination of the percentage of recent 
mollusca in the series. 
M’Coy, (M’Coy, ’61, p. 168) decided by the presence of a 
few species in our roweet Tertiaries, which had close allies in 
European strata, that the Victorian — were partly Mio- 
cene and partly Oligocene. 
Harris (Harris, 97, p.vrit.) would use phylogeny, © which, 
rightly understood, . . . is a broader and surer basis 
for classification of the various horizons,,and might be made 
to run pari passu with the Lyellian method.” This plan is, 
of course, merely the comparative method in a somewhat 
sublimated form. 
Some authors advocate the employment of the comparative 
method as applied to mollusca alone, or im great part; 
others would attach more importance to such wide-ranging 
forms as sharks and whales; while others, again, have regard 
to the fauna as a whole. Some would fix their attention on 
the striking transgressing forms, andsopiead for a younger or 
an older age, as the case might be, than the fauna, as a 
whole, would indicate; while others, finally, would ransack 
the Tertiary fauna of the Northern Hemisphere for close 
resemblances, and then correlate our beds with those which 
show the greatest number. 
Tt wili, I think, be readily advaitted that tae methed cf 
comparison in all its forms has dangers of its own, and 
these, grave ones. Do we know, for insiance, in which 
direction migration took place—was it in any particular 
instance from north to south, or vice verad? Do close 
resemblances aecessarily imply very close paylepene 
