GRAPTOLITES OF AUSTRALIA 
51 
New South Wales and Diplograptiis sp. in the Neranleigh 
Series of the Brisbane Series, an occurrence that he assigns 
to an horizon about the A^alentian of Britain. 
Third Period : 1932 to Present. 
This may be termed the period of systematization. In 1932 
the graptolite fauna was well enough known to subdivide the 
liower Ordovician strata into series and zones, hut the 
problem confronting systematists was where to fix their 
limits. It was known that the zones as constituted by T. S. 
Hall had not been based on the best principles of zoning, 
but it was difficult to adjust them without causing confusion. 
In 1932 W. J. Harris and R. A. Keble (121) systematized 
the subdivision of the Lower Ordovician largely on the basis 
laid down by T. S. Hall. They elevated his zones to series 
and subdivided each of these series into five zones. 
W. J. Harris (138) suggested a further subdivision of the 
Darriwil, and he and D. E. Thomas (157) revised the sub- 
divisions of all previous workers and added new series. 
1932 —The systematization of the Victorian Lower Ordo- 
vician succession by W. J . Harris and R. A. Keble (121) is 
as follows : 
DARRIWIL SERIES. 
Zone Typical Locality 
D1 Bendigo East 
Zonal Species 
Didymograptns 
nodosus 
Atopograptus 
woodwardi 
Brachiograptus 
etaformis 
Associated Forms 
Cardiograptus crawfordi 
Climacograptus 
Didymograptns caduceus 
(rare) 
Phyllograptus nobilis 
Lasiograptus 
Glossograptus 
Diplograptus 
Cryptograptus tricornis 
Trigonograptus ensiformis 
Tetragraptus quadribrachi- 
atus 
D2 Loc. 7SZ Geol. Diplograptus 
Surv. Vic. austrodentatus 
Sutherland’s Creek 
Steiglitz 
D3 Castlemaine-Mary- Cardiograptus 
borough Railway morsus 
W. of Strangways 
D. caduceus 
T rigonograptus 
Glossograptus 
C. tricornis 
Tetragraptus 
D. caduceus 
D. v-deflexus 
Tetragraptus 
Phyllograptus 
Diplograptus gnomonicus 
Trigonograptus 
