GRAPTOLITES OF AUSTRALIA 
61 
viaii and considered the sequence to be Keilorian, Mel- 
boiuTiian, and Yeringian, the Keilorian being the oldest. 
They correlated the Keilorian with the Lower Silurian or 
Llandovery Series of Britain; over these beds, at Keilor, 
come beds with Monogmptus riccartonensis, indicating 
Middle Silurian or Wenlock age. They correlated the Mel- 
bournian with the Lower Ludlow Series of the Upper Silurian 
of Britain, and the Yeringian with the Upper Ludlow. 
They discussed the lithological characters and fossil con- 
tents of the Keilorian, Melbournian and Yeringian in the 
Melbourne-Lily dale-Upper Yarra district as well as in other 
})arts of Victoria. 
W. J. Harris (138) in an important contribution discussed 
an area including the Parishes of Wellsford, Stratlificldsaye 
and Sedgwick with adjacent portions of other ])arisbes, par- 
ticularly in regard to the Darriwilian. He gave the genei'al 
distribution of the graptolite series and an outline of the 
zoning of the Darriwilian as high as the D2 Zone. He con- 
tended that the incoming of the Diplograptidae in force in 
the 1)2 Zone marks a very important stage in the gra])tolite 
succession and discussed the relationsbi]) of the D2 beds to 
the lower zones. He describeil bve sections from east to 
west across the area, and showed that there is a normally 
descending series of beds to the Wliitelaw Fault, and that 
above the D2 horizon two zones may l)c distinguished with 
])ossible passage beds, (a) a zone characterized by Diplo- 
(jmptus (Glijptograptus) intersitiis and Didgmograptus com- 
jn'essus, and (b) a higher zone characterized by DipJograptus 
( Mesograptus) dccoratus and Didgmogmptm nodosii.H. 
These zones may be I’ecognized throughout the area. He 
maintained that field and biological evidence fixes the posi- 
fion of the zones already mentioned and that elsewhere in 
Victoria a higher zone in the Lower Ordovician can be recog- 
nized, while the basal graptolite bed of the Upper Ordovician 
(as at Ba 67 Quarter Sheet 6 SE.) should also be included in 
a Diplograjduff series. In regard to the zoning of the Dar- 
i-iwilian and Castlemanian in Victoria, be stated that the 
grouping of zones from 1)2 to basal Upper Ordovician inclu- 
sive, as a Diplograptus series, leads to an attempt to treat 
lower beds in the same way. He states that the breaks 
between the typical sei-ies are largely artificial and suggests 
that the zones below the Diplograptus series, i.e., from D3 
downwards to 04 (inclusive) may be regarded as an Isograp- 
tus series. Immediately below this series are passage beds 
characterized by Didgmograptus protohifidus Elies, while 
