Cambrian and early Tremadoc rocks of the Llangynog Inlier, Dyfed, South Wales

1992 ◽  
Vol 129 (5) ◽  
pp. 543-552 ◽  
Author(s):  
J. C. W. Cope ◽  
A. W. A. Rushton
Keyword(s):  
Upper Cambrian ◽  
South Wales ◽  
Unconformable Contact

AbstractUntil recently no Cambrian rocks were known in the Llangynog area. Detailed mapping has now revealed a succession of ?Lower and Upper Cambrian rocks overlain by Tremadoc rocks. The Allt y Shed Sandstones (new) rest unconformably on the Precambrian, but have yielded no diagnostic fossils and are tentatively assigned to the Comley Series. Succeeding with faulted or unconformable contact is an Upper Cambrian Merioneth Series succession which includes in ascending order: conglomerates, sandstones and siltstones with olenid trilobites and resembling the Treffgarne Bridge Beds of the Haverfordwest area; micaceous shales and siltstones referred to the Ffestiniog Flags Formation; and black mudstones with calcareous concretions and a rich olenid fauna referred to the Dolgellau Formation. Succeeding the latter with possible disconformity is a succession belonging to the lower part of the Tremadoc Series and earlier than any rocks of that series hitherto recorded from the area.

Ordovician sponge spicules from New South Wales, Australia

1993 ◽  
Vol 67 (1) ◽  
pp. 28-41 ◽  
Author(s):  
B. D. Webby ◽  
J. Trotter
Keyword(s):  
Debris Flows ◽  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
New Genera ◽  
Siliceous Sponge ◽  
Upper Cambrian ◽  
South Wales ◽  
Sponge Spicules ◽  
First Time

An abundant, varied, and well-preserved assemblage of discrete sponge spicules of late Ordovician age is described from the Malongulli Formation of central New South Wales. It is associated with one of the most diverse Ordovician siliceous sponge faunas known. The assemblage occurs in allochthonous limestone blocks within breccia deposits of a predominantly graptolitic and spiculitic siltstone succession, and is composed mainly of hexactinellid spicule types. Included are a number of distinctive forms, recognized as new taxa—Silicunculus bengtsoni, Kometia cruciformis, Chelispongia prima, and Pseudolancicula exigua. All are new genera except Silicunculus Bengtson, 1986, which was previously described from the upper Cambrian of Queensland. The problematical Anomaloides reticulatus Ulrich, 1878, is reported for the first time from Australia. A wide variety of other diagnostic, but more generalized, spicule types also occurs, including stauractines, pinnular and nonpinnular pentactines and hexactines, ornamented oxyhexasters and echinhexasters, clavules, anchorate root-tufts, and uncinates. The pinnular pentactines may be assigned to the form genus Palaeorubus Ishiga (in Ishiga et al., 1987), interpreted incorrectly by Ishiga as a radiolarian. The sponges, discrete spicules, and radiolarians of these limestone clasts were transported in debris flows to a basinal setting from peri-platform oozes that formed on the flanks of the shallow offshore island-arc platform of the Molong High.

A revision of the stratigraphic nomenclature of the Cambrian–Ordovician strata of the Philipsburg tectonic slice, southern Quebec

2007 ◽  
Vol 44 (12) ◽  
pp. 1775-1790 ◽  
Author(s):  
O Salad Hersi ◽  
G S Nowlan ◽  
D Lavoie
Keyword(s):  
Middle Ordovician ◽  
Upper Cambrian ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Lower Ordovician ◽  
Stratigraphic Position ◽  
Stratigraphic Nomenclature ◽  
Unconformable Contact ◽  
Tectonic Slice ◽  
Upper Boundary

The Philipsburg tectonic slice is bounded to the west by a northeast–southwest-trending thrust fault (Logan’s Line) and preserves 10 formations of Middle (?) to Late Cambrian (Milton, Rock River, and Strites Pond formations), Early Ordovician (Wallace Creek, Morgan Corner, Hastings Creek, and Naylor Ledge formations), and early Middle Ordovician (Luke Hill, Solomons Corner, and Corey formations) age. The strata were previously assigned to the Philipsburg Group. Early correlations between the Philipsburg succession and coeval strata of the St. Lawrence Platform were mainly based on sparse macrofauna and inferred stratigraphic position. Unconformities at the Cambrian–Ordovician and Early Ordovician – Middle Ordovician boundaries occurring in autochthonous St. Lawrence Platform and the allochthonous Philipsburg succession (Philipsburg tectonic slice) highlight new stratigraphic interpretations between the inner-shelf (St. Lawrence Platform) and the outer-shelf (Philipsburg) successions. The succession in the Philipsburg tectonic slice is divided into three new groups. The Middle (?) to Upper Cambrian Missisquoi Group (new) includes the Milton, Rock River, and Strites Pond formations. The upper boundary of the Missisquoi Group is defined by the upper unconformable contact between the Upper Cambrian Strites Pond Formation and overlying Lower Ordovician Wallace Creek Formation. The Missisquoi Group correlates with the Potsdam Group of the St. Lawrence Platform. The Lower Ordovician School House Hill Group (new) includes the Wallace Creek, Morgan Corner, Hastings Creek, and Naylor Ledge formations. The upper boundary of this group is marked by a regionally extensive unconformity at the top of the Naylor Ledge Formation and correlates with the younger Beekmantown-topping unconformity. The School House Hill Group is correlative with the lower to upper part of the Beekmantown Group (Theresa Formation and the Ogdensburg Member of the Beauharnois Formation) of the St. Lawrence Platform. The Middle Ordovician Fox Hill Group (new) consists of the Luke Hill, Solomons Corner, and Corey formations. This group correlates with the uppermost part of the Beekmantown Group (Huntingdon Member of the Beauharnois Formation and the Carillon Formation).

β-Mannosidosis: Myelin and oligodendrocyte lesions in brain and spinal cord

1984 ◽  
Vol 42 ◽  
pp. 694-695
Author(s):  
Kathryn L. Lovell ◽  
Margaret Z. Jones
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Genetic Disorder ◽  
Neurological Deficits ◽  
Axonal Spheroids ◽  
South Wales ◽  
Pendular Nystagmus ◽  
Myelin Deficits ◽  
Recessive Defect ◽  
Brain And Spinal Cord

Caprine β-mannosidosis, an autosomal recessive defect of glycoprotein catabolism, is associated with a deficiency of tissue and plasma -mannosidase and with tissue accumulation and urinary excretion of oligosaccharides, including the trisaccharide Man(β1-4)GlcNAc(βl-4)GlcNAc and the disaccharide Man(β1-4)GlcNAc. This genetic disorder is evident at birth, with severe neurological deficits including a marked intention tremor, pendular nystagmus, ataxia and inability to stand. Major pathological characteristics described in Nubian goats in Michigan and in Anglo-Nubian goats in New South Wales include widespread cytoplasmic vacuolation in the nervous system and viscera, axonal spheroids, and severe myelin paucity in the brain but not spinal cord or peripheral nerves. Light microscopic examination revealed marked regional variation in the severity of central nervous system myelin deficits, with some brain areas showing nearly complete absence of myelin and other regions characterized by the presence of 25-50% of the control number of myelin sheaths.

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