The Late Cambrian to Early Ordovician sequence on the Denison Range, southwest Tasmania

A well-exposed middle Late Cambrian to Early Ordovician clastic sequence, herein referred to as the Denison Subgroup, unconformably overlies Middle Cambrian rocks on the Denison Range and is conformably overlain by Ordovician limestone. Four formations are recognized. The basal Singing Creek Formation (720 m) consists of interbedded siltstone, quartzwacke turbidites, siliceous fine conglomerate, and slump sheets, and contains an abundant Franconian trilobite-brachiopod fauna. It grades upwards into the Great Dome Sandstone (510 m), a shallow marine-deltaic-fluvial sequence of crossbedded quartz sandstone, siltstone and fine conglomerate, with a sparse fauna of probable Late Cambrian age. Above this the Reeds Conglomerate (1560 m) comprises largely non-marine pink siliceous conglomerate and cross-bedded sandstone, probably deposited on alluvial fans. This grades into the marine Squirrel Creek Formation, comprising a lower sandstone member (150 m) with worm burrows and gastropods, a siltstone- limestone member (150 m) with an abundant Early Ordovician shelly fauna, and an upper sandstone member (300 m). The Denison Subgroup is approximately equivalent to the pre-limestone part of the Junee Group in the 'original area of Lewis, and to the Owen Conglomerate of western Tasmania

An Early Miocene flathead. (Pisces Platycephalidae) from Wynyard, Tasmania

A well-preserved flathead skull from the Early Miocene marine beds near Wynyard is described. A comparison with the modern sand flathead Platycephalus bassensis Cuvier reveals a very close similarity

Revised terminology of the Late Cambrian - Ordovician sequence of the Florentine - Denison Range area, and the significance of the "Junee Group"

The area of Lewis's original "Junee Series" is unsuitable as a basis for definitive stratigraphy and correlation,even with units in adjacent areas. A review of the various usages and concepts associated with the "Junee Group" indicates considerable diversity in meaning and application of the term, and suggests that the sequences are better considered in terms of a lower clastic unit and an upper limestone unit rather than as a single group. Accordingly, the Late Cambrian-Ordovician sequence in the Florentine Synclinorium is defined in terms of the Denison Subgroup, comprising four formations between the basal unconformity on the Denison Range and the base of the limestone, and the Gordon Subgroup, comprising three limestone formations and the Westfield Beds. These two Subgroups together approximate to the "Junee Group"

A record of aboriginal implement sites in the Queenstown area, Tasmania

Sites containing aboriginal flaked stone implements have been discovered in the Queenstown area, some 30 km inland from the west coast of Tasmania. The sites occur mainly on low ridge tops along the East Queen River and Reservoir Creek, and have been exposed only after removal of the original cover of rainforest and peat around the mine area. They suggest extensive inland habitation by the aborigines prior to the establishment of the now-widespread rainforest

Ordovician Snatigraphy of the Florentine Synclinorium, south-west Tasmania

The Florentine Synclinorium consti tutes the type area of the Ordovician Junee Group in Tasmania, and the group is herein re-defined according to the formations present in this area. The base on the western side is formed by the Reeds Conglomerate, a unit of siliceous fanglomerate up to l,560 m thick lying conformably above a thick Upper Cambrian sequence on the Denison Range. The laterally-equivalent sandstone unit on the southeastern side is also given formation status (Tim Shea Sandstone). The overlying sequence of marine sandstone and siltstone is designated the Florentine Valley Formation, and is of Late Tremadocian-Arenigian age. A sub-unit of siltstone and limestone occurs in the middle part of the formation in some areas, but is not given formal status pending further mapping. The "Gordon Limestone", subdivided into three formations, becomes the Gordon Limestone Sub-Group. The basal Karmberg Limestone, of Upper Canadian -? Chazyan age, includes a mappable chert-rich unit which forms chert- covered ridges and is designated Wherretts Chert Member. The Cashions Creek Limestone, corresponding to the “Maclurites-Girvanella zone" of earlier reports, succeeds the Karmberg Limestone. Above this, and forming the bulk of the sequence, is the Benjamin Limestone, consisting of three members, viz. Lower Limestone Member, Lords Siltstone Member, Upper Limestone Member. A characteristic coral fauna with Favosites and cateniporines occurs near the top of the latter member, and includes conodonts which suggest an age not younger than Maysvillian. Above the limestone sequence and transitional with the overlying Eldon Group sandstone is a unit of siltstone and fine sandstone designated Westfield Beds. These contain a fauna correlated with the Richmondian, and the fauna in the overlying sandstone also appears to be Late Ordovician

Tertiary volcanic rocks of far N.W. Tasmania

The Tertiary volcanic rocks of far north-west Tasmania comprise tuffs, pillow-basalts and breccias, entrail basalts, and massive basalts, and eruptions appear to have occurred at several intervals from Lower to Upper Tertiary times. Sea level fluctuations have been important in determining the form assumed by the flows. The lavas were predominantly saturated black glass olivine basalts with one extrusion of undersaturated olivine alkali basalt. The oldest of the volcanics is a widespread formation of sub-aqueously deposited tuffs. These were followed, after a period of erosion, by massive basalts, including a basal zone of entrail lava, which were probably erupted during an Upper PalaeoceneUpper Eocene marine regression. Extensive submarine eruptions followed, resulting in the formation of large cones composed predominantly of pillow breccias. These were probably formed during a marine transgression in the Upper EoceneUpper Oligocene. A period of erosion, probably subaerial, dissected these cones, and limestones were later deposited on their eroded flanks during a major marine transgression in the Miocene. A final volcanic phase, probably during an Upper Miocene-Pliocene marine regression, saw widespread eruptions of massive basalts, some of which filled valleys eroded in the older volcanics and sediments. The magmatic history of the eruptions in this area appears to be significantly different from that of the Cainozoic volcanics of Victoria

Monopolin subunit Csm1 associates with MIND complex to establish monopolar attachment of sister kinetochores at meiosis I

Sexually reproducing organisms halve their cellular ploidy during gametogenesis by undergoing a specialized form of cell division known as meiosis. During meiosis, a single round of DNA replication is followed by two rounds of nuclear divisions (referred to as meiosis I and II). While sister kinetochores bind to microtubules emanating from opposite spindle poles during mitosis, they bind to microtubules originating from the same spindle pole during meiosis I. This phenomenon is referred to as mono-orientation and is essential for setting up the reductional mode of chromosome segregation during meiosis I. In budding yeast, mono-orientation depends on a four component protein complex referred to as monopolin which consists of two nucleolar proteins Csm1 and Lrs4, meiosis-specific protein Mam1 of unknown function and casein kinase Hrr25. Monopolin complex binds to kinetochores during meiosis I and prevents bipolar attachments. Although monopolin associates with kinetochores during meiosis I, its binding site(s) on the kinetochore is not known and its mechanism of action has not been established. By carrying out an imaging-based screen we have found that the MIND complex, a component of the central kinetochore, is required for monopolin association with kinetochores during meiosis. Furthermore, we demonstrate that interaction of monopolin subunit Csm1 with the N-terminal domain of MIND complex subunit Dsn1, is essential for both the association of monopolin with kinetochores and for monopolar attachment of sister kinetochores during meiosis I. As such this provides the first functional evidence for a monopolin-binding site at the kinetochore