Marcusodictyon Bassler from the Lower Ordovician of Estonia: not the earliest bryozoan but a phosphatic problematicum

Marcusodictyon priscum (Bassler 1911) from the Tremadocian Ungulite Sandstone (A2) of Jegelecht Falls, Estonia, is redescribed following SEM study of type and other specimens. The fossil consists of a polygonal network of low ridges known to exist only on the exterior surfaces of valves of the inarticulate brachiopod Obolus. Electron microprobe analysis demonstrates that, like its host substratum, Marcusodictyon is composed of calcium phosphate. This, together with the detailed morphology and dimensions of the ridge system, is used to negate Bassler's assignment of the genus to the ctenostome Bryozoa. Instead Marcusodictyon resembles the Silurian problematicum Gochtia Eisenack. The inferred growth pattern of Marcusodictyon suggests that it may have been a symbiont of a living brachiopod.     

Silicified wood of Early Miocene Nothofagus,Acacia and Myrtaceae (aff. Eucalyptus B) from the upper Lachlan valley,New South Wales

Three specimens of silicified wood, two transported and one probably in situ, have been found in association with Early Miocene basaltic lavas in the upper Lachlan valley, N.S.W. On the basis of their preserved structure, the three specimens have been identified as belonging to Nothofagus, Acacia, and the family Myrtaceae, respectively. The specimen of Nothofagus (one of the transported specimens) constitutes the first identification of a macrofossil of this genus from this interval in southeastern mainland Australia, while its conjunction with the myrtaceous specimens (one probably in situ) may indicate vegetation zonation according to elevation, as proposed on pollen evidence from Kiandra. Such zonation is not demanded by the upper Lachlan evidence, however, but if it is favoured, reconstruction of the Early Miocene geography of the upper Lachlan constrains the maximum elevation above the locality of the myrtaceous fossils to be 350 m.     

Middle Ordovician faunal spatial differentiation in Baltoscandia and the Appalachians

The distributional differentiation of Baltoscandian Middle Ordovician shelly faunas in terms of confacies belts has a counterpart in the southern and central Appalachians, where three belts, parallel to the mountain chain, are distinguished: the Blount, Tazewell and Lee Confacies Belts. As in Baltoscandia, the boundaries between these belts are sharp. The Blount Belt high-diversity shelly macrofauna is closely similar to Scoto-Appalachian faunas of northeastern Ireland and southwestern Scotland (Girvan). The Lee Belt fauna is virtually the same as that of the North American Midcontinent, and that of the Tazewell Belt is transitional between those of the Blount and Lee Belts. The ecological factors causing the confacies differentiation are currently not clearly understood but the differentiation was evidently not due to a single factor such as water depth, although this factor was apparently important for second-order differentiation (biofacies) within a confacies belt. The spatial differentiation patterns of the shelly, graptolite, and conodont faunas do not always coincide, suggesting that the factors controlling the distribution were largely specific for each fauna.     

Tertiary gymnosperms from Tasmania: Araucariaceae

Three new species of the Araucariaceae are described from leaf remains, Araucaria readiae from the Early Eocene Regatta Point flora, A. hastiensis from the Middle-Late Eocene Hasties flora, and Agathis tasmanica from the Early Oligocene-Early Miocene Little Rapid River flora. Additionally, emended diagnoses are presented for Araucarioides linearis and A. annulata. A. readiae is the first organically preserved species in the section Eutacta described from Tasmania, A. hastiensis is the first record of a species not in section Eutacta in Tasmania, and A. tasmanica is the first record of Agathis in Tasmania. These species, along with other records from south-eastern Australia indicate the presence of a high diversity of araucarian species in the region in the Early-Middle Tertiary, although no species survive there today. Climatic change and competition from angiosperms may have led to their demise in that region.     

Cretaceous foraminiferal biostratigraphy of Queensland

The distribution of foraminiferids within Aptian-Albian marine deposits of the Laura, Carpentaria, Eromanga, and Surat Basins in Queensland is described. The foraminiferal distribution patterns are largely a reflection of environmental differences which existed within the basins. Among the benthonic foraminiferids, two major faunal associations are recognized: the Ammobaculites association reflecting hyposaline, cool, shallow water conditions; and the Marssonella association indicating normal marine, open continental shelf environments. As the faunal content of these associations is markedly different, separate time-stratigraphic zonations are proposed: the Ammobaculites association is divided into the Textularia cushmani zone (early Aptian), T. cushmani-Bigenerina pitmani zone (late Aptian), B. pitmani zone (late Aptian), B. pitmani-Riyadhella crespinae zone (early Albian), and R. crespinae zone (early-late Albian); the Marssonella association contains the Anomalinoides intermedia zone (early-middle Albian in Queensland), and the A. cenomanica zone (late Albian in Queensland). Planktonic foraminiferids, which occur with both benthonic associations, are used to correlate the benthonic zonal schemes, and are themselves zoned separately: Hedbergella planispira zone (early-middle Albian), H. infracretacea zone (middle-early late Albian), and the H. delrioensis zone (late Albian). International stage correlations are based on certain foraminiferids and associated ammonites.

The distribution of foraminiferids in Queensland during the late Early Cretaceous suggests that 1, climate exerted a uniform influence over the region; 2, cool, hyposaline, shallow water conditions prevailed over much of Queensland; 3, open marine shelf conditions (of normal salinity) existed during the Albian in the Laura and northeastern Carpentaria Basins; and 4, during the Albian, at least, there was a northern seaway to the open ocean.     

Cenozoic Elaeocarpus (Elaeocarpaceae) fruits from Australia

Fossil Elaeocarpus species with spherical fruits are redescribed and compared with extant species. Information on the distribution of E. mackayi (F. Muell.) Kirchheimer and E. spackmaniorum Rozefelds is provided. Additional notes on the morphology of E. spackmaniorum Rozefelds are also included; and collections from Guildford, in Victoria, are considered conspecific. Elaeocarpus occultus sp. nov. is described from the Haddon deep leads in Victoria; it has a spherical inner mesocarp, bastionate ornamentation, foraminae in the mesocarp wall and mesosutural ridges, which represent a combination of characters unique within extant Australian Elaeocarpus species. The fossil fruit record of Elaeocarpus is systematically significant because it demonstrates that the genus was morphologically diverse by the Miocene in Australia. Biogeographically, the genus also had a different, or more widespread distribution in Australia during the Cenozoic.