C--Cycloceras ibex, Sow. sp. Silurian (Melb.) Victoria D--Phragmoceras subtrigorium, McCoy. Mid Devonian. Victoria E--Gastrioceras jacksoni, Eth. fil. Carbopermian. W. Australia F--Agathiceras micromphalum, Morris sp. Carbopermian. N.S.W. ] =Silurian Cephalopods.--= Silurian cephalopods are more generally distributed, and in Victoria constitute an important factor in the molluscan fauna of that system. _Orthoceras_ and _Cycloceras_ are the best known genera, represented by _Orthoceras capillosum_, found near Kilmore, Victoria; _O. lineare_ (Fig. 105 B), from the Upper Yarra; _Cycloceras bullatum_, from the Melbournian of Collingwood and Whittlesea; and _C. ibex_ (Fig. 105 C) from South Yarra and Flemington, in both Melbournian shale and sandstone. The latter species occurs also at Rock Flat Greek, New South Wales. Other Victorian species are _Kionoceras striatopunctatum_, a well-known European fossil with a reticulated and beaded ornament, found near Warburton and at McMahon's Creek, Upper Yarra. _Orthoceras_ is also recorded from Tasmania and from the Wangapeka beds of Baton River, New Zealand. _Cyclolituites_, a partially coiled nautilian is recorded from Bowning, near Yass, New South Wales; whilst the closely related _Lituites_ is noted from the Silurian of Tasmania. =Devonian Cephalopods.--= The only genus of cephalopoda at present recorded from the Devonian of Victoria is _Phragmoceras_ (_P. subtrigonum_) (Fig. 105 D), which occurs in the Middle Devonian Limestone of Buchan, E. Gippsland. From beds of similar age in New South Wales _Orthoceras_, _Cyrtoceras_ and _Goniatites_ have been noted; whilst the latter genus also occurs near Kimberley, Western Australia. In Queensland _Gyroceras philpi_ is a characteristic shell, found in the Fanning and Reid Gap Limestones of the Burdekin Formation (Middle Devonian). =Carbopermian Cephalopods.--= The Carbopermian rocks of New South Wales have yielded _Orthoceras striatum_, _Cameroceras_, _Nautilus_ and _Agathiceras micromphalum_ (Fig. 105 F). In Queensland the Gympie Formation contains _Orthoceras_, _Gyroceras_, _Nautilus_, _Agathiceras micromphalum_ and _A. planorbiforme_. In Western Australia the Kimberley rocks contain _Orthoceras_, _Glyphioceras sphaericum_ and _Agathiceras micromphalum_; whilst the largest known Australian goniatite, _Gastrioceras jacksoni_ (Fig. 105 E) is found in the Irwin River District. _Actinoceras hardmani_ is an interesting fossil from the Carbopermian of Lennard River, N.W. Australia. In Tasmania the genera _Orthoceras_ and _Goniatites_ have been recorded from beds of similar age. =Triassic Cephalopods.--= For Triassic cephalopoda we look to New Zealand, where, in the Mount Potts _Spiriferina_ Beds of the Kaihiku Series a species of _Orthoceras_ has been recorded. The Wairoa Series next in succession contains _Orthoceras_ and an Ammonite. =Jurassic Cephalopods.--= [Illustration: =Fig. 106--MESOZOIC and CAINOZOIC CEPHALOPODA.=