GRAPTOLITES OF AUSTRALIA 
71 
Castlemaine Series or Castlemanian (as now restricted) 
Cal Zone of Isograptus caduceus var. lunata. Entry of I. caduceus 
var. lunata in force. (“C3”). 
Ca3 Zont oi Isograptus caduceus var. victoriae. (“C2”). 
Ca3 Zone of Isograptus caduceus var. maxintus and var. maximo-diver- 
gens. (“Cl”). 
Yapeen Series or Yapeenian 
(Formal acceptance of name previously suggested to include the lower 
portion of the Darriwilian) 
Yal Zone of Oncograptus. (“D5”). 
Ya2 Zone of Cardiograptus. (“D4 and D3”). 
Middle Ordovician 
(Term established, with usage rather different from that in Great Britain, to 
include the upper portion of the Darriwilian and one higher zone) 
M.O.l Zone of Diplograptus (Glyptograptus) austrodentatus. Entry of 
the Diplograpti in force. (“D2”). 
M.0.2 Zone of D. (G.) iniersitus (“Dla”) 
M.0.3 Zone of D. (G.) decoratus. (“Dlb”). 
M.0.4 Zone of D. (G.) ieretiusculus (formerly considered basal Gis- 
bornian). Glossograptus hincksii abundant, entry of Climacograpti. 
Upper Ordovician 
Regarding tlie Upper Ordovician, Harris and Thoinas, 
cominenting on the divisions of Thoinas and Kehle (126) into 
3. 
2 . 
1 . 
Bolindian. 
Eastonian. 
Gisbornian. 
state that: 
1 Apart from the zone of Glyptograptus teretiusculus, which has been 
included in the Middle Ordovician, the zone of Nemagraptus and zone ot 
Climacoqraptus peltifcr represent the Gisbornian. 
2. The lowest beds of the Eastonian were not ascribed to any dehnite 
zone, but the upper part was correlated with the zone of Dicranograptus 
3 ^ The Bolindian was stated to contain three characteristic assemblages 
(a) At the base Diplograptus quadrimucronatus , Dicellograptus 
elegans, and Climacograptus iubuliferus. 
(b) Pleurograptus sp. characterizes the middle portion 
('c') Still higher assemblages are characterized by Retiograptus pul- 
cherrimus, while Diplograptus sinuatus and D. tamanscus are also 
present. 
As a result of work in the Romsey and Emu Creek areas, 
Thomas subdivided the Upper Ordovician as follows: 
Zone of Dicellograptus cf. complanatus 
Zone of Pleurograptus 
Bolindian 
