(4) Darriwill Series. Characterised by Trigonograptus wilkinsoni. Also contain Diplograptus, Glossograptus and Lasiograptus, whilst Didymograptus is rare.
Lower Ordovician Graptolites, New Zealand.—
In New Zealand Lower Ordovician Graptolites are found in the Kakanui Series, at Nelson, north-west of South Island. Some of the commoner forms are Didymograptus extensus, D. caduceus, Loganograptus logani, Phyllograptus typus, Tetragraptus similis and T. quadribrachiatus.
Graptolites agreeing closely with those of the Lancefield Series of Victoria occur near Preservation Inlet in the extreme South-west, and have been identified as Clonograptus rigidus, Bryograptus victoriae and Tetragraptus decipiens.
Upper Ordovician Graptolites, Victoria.—
The Upper Ordovician rocks of Victoria, as at Wombat Creek and Mount Wellington in Gippsland, and at Diggers’ Rest near Sunbury, contain the double branched forms like Dicranograptus ramosus, Dicellograptus elegans and D. sextans; the sigmoidal form Stephanograptus gracilis; and the diprionidian (biserial) forms as Diplograptus tardus, Climacograptus bicornis, Cryptograptus tricornis, Glossograptus hermani and Lasiograptus margaritatus ([Fig. 75]).
Fig. 75—UPPER ORDOVICIAN and SILURIAN GRAPTOLITES.
A—Dicranograptus ramosus, J. Hall sp. Up. Ordovician. Victoria.
B—Dicellograptus elegans, Carruthers sp. Up. Ordovician. Victoria.
C—Diplograptus carnei, T. S. Hall. Up. Ordovician. N. S. Wales.
D—Climacograptus bicornis, J. Hall. Up. Ordovician. Victoria.
E—Glossograptus hermani, T. S. Hall. Up. Ordovician. Victoria.
F—Retiolites australis, McCoy. Silurian. Keilor, Victoria.
G—Monograptus dubius, Suess. Silurian. Wood’s Point, Victoria.
Upper Ordovician Graptolites, New South Wales.—