PRESIDENT’S ADDRESS. 177 
species of Dictyonema which are just as typically Lower 
rdovician in Europe. In America Clonegraptus flexiis 
is associated with such forms as occur at Bendigo, the next 
horizon above the Lancefield beds, which do not contain 
them, while C. rigidus is found with Loganograptus logant. 
Now, in Australia the last-named does not put in an appear- 
ance till the rich fauna of Bendigo and a great part of that 
of the Castlemaine series, which is younger than the Bendigo 
series, has disappeared entirely. Another example may be 
quoted. The group characterised by Didymograpius btfidus, 
the “tuning-fork graptolites,” as they are sometimes called, 
ig in Europe and America characteristic of Upper Arenig, 
when the complexly branched forms, and the peculiar Phyl- 
lograptus, have already died out. With us their horizon is 
lower and their range very short. Phyllograptus, Clono- 
graztus, and Dichograptus long survive theta, while Logano- 
greptus logant only put in an appearance when they, in 
their turn, have almost passed away. Graptolites are not 
always easy of recognition, but these forms all belong to 
readily-recognisable groups; the specific determinations, it is 
possible; may be incorrect, but the generic cannot be con- 
founded. ' 
Tae Basis or Tae CLASSIFICATION OF THE AUSTRALIAN 
TERTIARIES. 
When we come to the Tertiaries, the evidences of irans 
gression are very well marked, and, owing main!y to this, 
the determination of them age is a task of great difficulty. 
It is generally admitted that, measured im years, the Ter- 
tiary perieds are much shorter, than. those of the Paleozoic 
and Mesozoic eras; thus, it follows that the attempt to 
correlate them with those at the Antipcdes is more on 4a 
levei with an attempt to correlate, say, Wenlock or Bajocian 
throughout the world. It is easy enough te recognize Ter- 
tiary strata anywhere, and to correlate them with others 
ry, but we do not yet know whether we aan assert 
Hocene, Miocene, or Pliocene bere in -Aus 
xt enough to say that certain beds are Hocene 
fauna has reached what may be termed 
the same stage of development that the Eocene fauna of 
Kurops has done. Our aim must be more definite than this, 
though perhaps, we shall never reach the mark. Hometasy 
. 7 ’ . 2 y - - a 
is not the end; contempsraneity is. The solution of many 
quésticus of phylogeny, the place of origin of certain types, 
and consequently the place ‘where we must look for their 
ancestars, aro problems the answers to which will depend, 
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