Denis Bates - Academia.edu (original) (raw)

Papers by Denis Bates

Research paper thumbnail of Contrasting modes of construction of Retiolite - type Rhabdosomes

Acta Palaeontologica Polonica, 1978

Investigation of retiolite-type rhabdosomes has so far revealed two contrasting types of construc... more Investigation of retiolite-type rhabdosomes has so far revealed two contrasting types of construction: 1. In a morphological series including Reteograptus geinitzianus, Gothograptus nassa, Holoretiolites spp. and 'Retiolies' sp. it is possible to demonstrate that sclerotization of the periderm secreted between the zooid and its mantle evagination became progressively localized, culminating in the formation of the highly specialized and sparse framework of Holoretiolites and 'Retiolites' sp. 2. In Retiolites geinitzianus (Barrande) the same kind of peridermal secretion combined with localized sclerotization to produce a superficially similar type of rhabdosome to some of those in the above morphological series, but with a quite different relationship to the secretary tissues of the zooids. Secretion and sclerotization of fibrous strips or 'bandages' seems to have occurred in many normal graptoloids, but resulting in the formation of a continuous cortex. The restriction of the sc1erotized 'bandages' in the retiolites, so as to produce a sparse but resilient framework, suggests that their function was mechanical rather than protective. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see creativecommons.org), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Research paper thumbnail of <i>Kirkigraptus</i>, a New Retiolitid Graptolite from Poland

Acta Palaeontologica Polonica, 2008

The new retiolitid graptolite Kirkigraptus inexpectans gen. et sp. nov., from the Neodiversograpt... more The new retiolitid graptolite Kirkigraptus inexpectans gen. et sp. nov., from the Neodiversograptus nilssoni Biozone of the Bartoszyce borehole, Poland is described. It is unique among the retiolitids not having a preserved virgella or ancora. Instead the most proximal structures are two round proxi−lateral lists, joining the two genicular lists of the first thecae, connecting the two sides of the rhabdosome. The lists are interpreted as a possible homologue of the distal edge of the ancora umbrella in typical retiolitids. The size of rhabdosome with large proximal lateral orifices, and the ventral panels of thecae with mid−ventral lists, are similar to those of Plectograptus, whereas the two ancora sleeve panels consisting of spaced horizontal lists only, resemble those of Valentinagraptus. It is possible that the new retiolitid may represent a new pattern of development of the proximal end of the rhabdosome, different from that in all other retiolitids.

Research paper thumbnail of The lower Palaeozoic brachiopod and trilobite faunas of Anglesey

Bulletin of the British Museum of Natural History, 1968

Research paper thumbnail of Mode of secretion of graptolite periderm, in normal and retiolite graptolites

Geological Society, London, Special Publications, 1986

Summary The construction of graptolite periderm is discussed with particular reference to the riv... more Summary The construction of graptolite periderm is discussed with particular reference to the rival extra-thecal tissue (secretion) and pterobranch (mortaring) models, and it is concluded that only the former model fits the observed structures. Evidence from a number ...

Research paper thumbnail of A Lower Ordovician Gastropod from Anglesey

Geological Magazine, Jun 1, 1963

Matherella (?) acuticostata sp. nov. is described from the Lower Ordovician of Trefor, near Bryng... more Matherella (?) acuticostata sp. nov. is described from the Lower Ordovician of Trefor, near Bryngwran, in mid Anglesey.

Research paper thumbnail of Reassessment of Arenig and Llanvirn age (early Ordovician) brachiopods from Anglesey, north-west Wales

Palaeontology, 1978

... The Treiorwerth, Bod Deiniol, and closely related Nantannog Formations form a sedimentary com... more ... The Treiorwerth, Bod Deiniol, and closely related Nantannog Formations form a sedimentary complex on Anglesey that is re-examined here in the light of evidence indicating their deposition in shallow water surrounding an island or group of islands, the Irish Sea horst. ...

Research paper thumbnail of Construction of Graptolite Tubaria

John Wiley & Sons, Ltd eBooks, Mar 18, 2017

Research paper thumbnail of The Retiolitid Graptolites

John Wiley & Sons, Ltd eBooks, Mar 18, 2017

Research paper thumbnail of The ultrastructure, development, and systematic position of the graptolite genus Mastigograptus

Acta Palaeontologica Polonica, Sep 6, 2011

Fragments of rhabdosomes isolated by chemical treatment from an erratic boulder of Baltic origin ... more Fragments of rhabdosomes isolated by chemical treatment from an erratic boulder of Baltic origin and ?Middle Ordovi− cian age, provisionally assigned to Mastigograptus aff. tenuiramosus (Wallcott, 1881) were studied with SEM. Although exceptionally well preserved, remains lack the thin−walled free portions of thecae. Rhabdosomes are provided with a strongly developed basal disc, short stem and many branched stipes. The latter consist of heavily corticalized chains of stolothecae with alternately disposed thecal bases. Stolothecae display a morphological gradient and increase in size and change in shape distalwards. The stolon system studied with SEM on naturally and artificially broken specimens, as well as traced through open thecal bases, reveals a regular triad budding but no stolon inside the stolothecal cavity. We tenta− tively suggest that crassal lining, recognized earlier by TEM studies, corresponds to an unusually inflated stolonal stolon, filling the entire thecal cavity and adhering tightly to stolothecal wall. The systematic position of Mastigograptus, a mat− ter of long debate, seems to be defined by a number of structural features which imply a distinct difference between genus in question and all known orders of sessile graptolites. The order Mastigograptida nov. and the family Mastigograptidae nov. are proposed.

Research paper thumbnail of Graptolites, a fossil case-history of evolution from sessile, colonial animals to automobile superindividuals

Proceedings of the Royal Society of London, Jul 22, 1986

Research paper thumbnail of A Simple Class Exercise on Plate Tectonic Motion

Journal of Geological Education, Mar 1, 1990

Research paper thumbnail of Paleoecology of the Pterobranchia

John Wiley & Sons, Ltd eBooks, Mar 18, 2017

Research paper thumbnail of A Note on the Disposition of Fold Axes in the Silurian Strata around the Newry Granodiorite

Geological Magazine, Jun 1, 1960

An area of high, north-eastward plunge of b-axes has been mapped in Silurian greywackes around th... more An area of high, north-eastward plunge of b-axes has been mapped in Silurian greywackes around the mouth of Strangford Lough, N. Ireland. Reconnaisance over a wider area to the south-west is consistent with the hypothesis that this steep plunge is due to the upward push exerted during the emplacement of the Newry Granodiorite. A near surface extension of the intrusion towards the east-north-east is inferred.

Research paper thumbnail of Excessive thickening of the cortical layer in graptolites

Proceedings of the Yorkshire Geological Society, Nov 1, 2011

SUMMARY A number of graptolites with thickened periderm, both dendroids and graptoloids, have bee... more SUMMARY A number of graptolites with thickened periderm, both dendroids and graptoloids, have been examined with the SEM. The thickening is by the deposition of layers of ectocortical tissue, clearly as bandages in the graptoloids. In Colonograptus colonus ...

Research paper thumbnail of Probable orthocone skip and roll marks from the Aberystwyth Grits

Geological Magazine, 1974

SummarySkip and roll marks, probably the impressions of orthocones, are described from the Aberys... more SummarySkip and roll marks, probably the impressions of orthocones, are described from the Aberystwyth Grits (Lower Silurian, mid-Wales).

Research paper thumbnail of The density of graptoloid skeletal tissue, and its implication for the volume and density of the soft tissue

Lethaia, Apr 1, 1987

ABSTRACT It has been proposed by many authors that a mechanism is necessary to achieve neutral bu... more ABSTRACT It has been proposed by many authors that a mechanism is necessary to achieve neutral buoyancy in graptoloids. Calculations are given to show the range of densities needed for both soft and skeletal tissues to achieve this, and it is concluded that a large volume of soft tissue, containing low density fats, is the most likely mechanism. This is not readily compatible with the rhabdopleuran model of the graptolite mid.

Research paper thumbnail of The role of extrathecal tissue in the construction and functioning of some Ordovician and Silurian retiolitid graptoloids

Bulletin of The Geological Society of Denmark, Jun 1, 1987

Research paper thumbnail of Retiolite nomenclature and relationships

Journal of the Geological Society, Jul 1, 1990

... Retiolite nomenclature and relationships DEB BATES Institute of Earth Studies, University Col... more ... Retiolite nomenclature and relationships DEB BATES Institute of Earth Studies, University College of Wales, Aberystwyth, Dyfed SY23 3DB, UK ... For Bulman this cast doubt on the unity of the group, although he did unite them within the single family. Rickards et al. ...

Research paper thumbnail of The structure of the Lower Palaeozoic rocks of Anglesey, with special reference to faulting

Geological Journal, Apr 30, 2007

The principal structures of the Lower Palaeozoic rocks of Angelsey are described. Tight folding, ... more The principal structures of the Lower Palaeozoic rocks of Angelsey are described. Tight folding, with variably developed slaty cleavage and a first phase of reverse faulting, took place probably in late Silurian times, along axes which are parallel to pre‐Cambrian foliation trends. A second phase of reverse faulting followed basic dyke intrusion and was succeeded by normal faulting and mineralization. Joint production was a comparatively late feature. A technique for analysing fault data, in terms of stress axes, is outlined and applied to faulting within the Lower Palaeozoic rocks.

Research paper thumbnail of The Stratigraphy of the Ordovician rocks of Anglesey

Geological Journal, Apr 30, 2007

Arenig sandstones, grits and conglomerates rest unconformably on pre‐Cambrian rocks (the Mona Com... more Arenig sandstones, grits and conglomerates rest unconformably on pre‐Cambrian rocks (the Mona Complex) and are of variable thickness and facies. Higher Arenig and Llanvirn shales, grits, conglomerates, shaly breccias and ironstones are related to contemporaneous fault movements, with abundant slump structures and rare turbidites. A pre‐Caradoc break in sedimentation was followed by deposition of shales, cherty shales, sandstones, breccias and conglomerates on Llanvirn, Arenig and pre‐Cambrian rocks. The Carmel Head Thrust acted as a major line controlling sedimentation, with upthrow to the north. Lower Silurian graptolitic shales at Parys Mountain rest on an acid volcanic group of Caradoc (?) age.

Research paper thumbnail of Contrasting modes of construction of Retiolite - type Rhabdosomes

Acta Palaeontologica Polonica, 1978

Investigation of retiolite-type rhabdosomes has so far revealed two contrasting types of construc... more Investigation of retiolite-type rhabdosomes has so far revealed two contrasting types of construction: 1. In a morphological series including Reteograptus geinitzianus, Gothograptus nassa, Holoretiolites spp. and 'Retiolies' sp. it is possible to demonstrate that sclerotization of the periderm secreted between the zooid and its mantle evagination became progressively localized, culminating in the formation of the highly specialized and sparse framework of Holoretiolites and 'Retiolites' sp. 2. In Retiolites geinitzianus (Barrande) the same kind of peridermal secretion combined with localized sclerotization to produce a superficially similar type of rhabdosome to some of those in the above morphological series, but with a quite different relationship to the secretary tissues of the zooids. Secretion and sclerotization of fibrous strips or 'bandages' seems to have occurred in many normal graptoloids, but resulting in the formation of a continuous cortex. The restriction of the sc1erotized 'bandages' in the retiolites, so as to produce a sparse but resilient framework, suggests that their function was mechanical rather than protective. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see creativecommons.org), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Research paper thumbnail of <i>Kirkigraptus</i>, a New Retiolitid Graptolite from Poland

Acta Palaeontologica Polonica, 2008

The new retiolitid graptolite Kirkigraptus inexpectans gen. et sp. nov., from the Neodiversograpt... more The new retiolitid graptolite Kirkigraptus inexpectans gen. et sp. nov., from the Neodiversograptus nilssoni Biozone of the Bartoszyce borehole, Poland is described. It is unique among the retiolitids not having a preserved virgella or ancora. Instead the most proximal structures are two round proxi−lateral lists, joining the two genicular lists of the first thecae, connecting the two sides of the rhabdosome. The lists are interpreted as a possible homologue of the distal edge of the ancora umbrella in typical retiolitids. The size of rhabdosome with large proximal lateral orifices, and the ventral panels of thecae with mid−ventral lists, are similar to those of Plectograptus, whereas the two ancora sleeve panels consisting of spaced horizontal lists only, resemble those of Valentinagraptus. It is possible that the new retiolitid may represent a new pattern of development of the proximal end of the rhabdosome, different from that in all other retiolitids.

Research paper thumbnail of The lower Palaeozoic brachiopod and trilobite faunas of Anglesey

Bulletin of the British Museum of Natural History, 1968

Research paper thumbnail of Mode of secretion of graptolite periderm, in normal and retiolite graptolites

Geological Society, London, Special Publications, 1986

Summary The construction of graptolite periderm is discussed with particular reference to the riv... more Summary The construction of graptolite periderm is discussed with particular reference to the rival extra-thecal tissue (secretion) and pterobranch (mortaring) models, and it is concluded that only the former model fits the observed structures. Evidence from a number ...

Research paper thumbnail of A Lower Ordovician Gastropod from Anglesey

Geological Magazine, Jun 1, 1963

Matherella (?) acuticostata sp. nov. is described from the Lower Ordovician of Trefor, near Bryng... more Matherella (?) acuticostata sp. nov. is described from the Lower Ordovician of Trefor, near Bryngwran, in mid Anglesey.

Research paper thumbnail of Reassessment of Arenig and Llanvirn age (early Ordovician) brachiopods from Anglesey, north-west Wales

Palaeontology, 1978

... The Treiorwerth, Bod Deiniol, and closely related Nantannog Formations form a sedimentary com... more ... The Treiorwerth, Bod Deiniol, and closely related Nantannog Formations form a sedimentary complex on Anglesey that is re-examined here in the light of evidence indicating their deposition in shallow water surrounding an island or group of islands, the Irish Sea horst. ...

Research paper thumbnail of Construction of Graptolite Tubaria

John Wiley & Sons, Ltd eBooks, Mar 18, 2017

Research paper thumbnail of The Retiolitid Graptolites

John Wiley & Sons, Ltd eBooks, Mar 18, 2017

Research paper thumbnail of The ultrastructure, development, and systematic position of the graptolite genus Mastigograptus

Acta Palaeontologica Polonica, Sep 6, 2011

Fragments of rhabdosomes isolated by chemical treatment from an erratic boulder of Baltic origin ... more Fragments of rhabdosomes isolated by chemical treatment from an erratic boulder of Baltic origin and ?Middle Ordovi− cian age, provisionally assigned to Mastigograptus aff. tenuiramosus (Wallcott, 1881) were studied with SEM. Although exceptionally well preserved, remains lack the thin−walled free portions of thecae. Rhabdosomes are provided with a strongly developed basal disc, short stem and many branched stipes. The latter consist of heavily corticalized chains of stolothecae with alternately disposed thecal bases. Stolothecae display a morphological gradient and increase in size and change in shape distalwards. The stolon system studied with SEM on naturally and artificially broken specimens, as well as traced through open thecal bases, reveals a regular triad budding but no stolon inside the stolothecal cavity. We tenta− tively suggest that crassal lining, recognized earlier by TEM studies, corresponds to an unusually inflated stolonal stolon, filling the entire thecal cavity and adhering tightly to stolothecal wall. The systematic position of Mastigograptus, a mat− ter of long debate, seems to be defined by a number of structural features which imply a distinct difference between genus in question and all known orders of sessile graptolites. The order Mastigograptida nov. and the family Mastigograptidae nov. are proposed.

Research paper thumbnail of Graptolites, a fossil case-history of evolution from sessile, colonial animals to automobile superindividuals

Proceedings of the Royal Society of London, Jul 22, 1986

Research paper thumbnail of A Simple Class Exercise on Plate Tectonic Motion

Journal of Geological Education, Mar 1, 1990

Research paper thumbnail of Paleoecology of the Pterobranchia

John Wiley & Sons, Ltd eBooks, Mar 18, 2017

Research paper thumbnail of A Note on the Disposition of Fold Axes in the Silurian Strata around the Newry Granodiorite

Geological Magazine, Jun 1, 1960

An area of high, north-eastward plunge of b-axes has been mapped in Silurian greywackes around th... more An area of high, north-eastward plunge of b-axes has been mapped in Silurian greywackes around the mouth of Strangford Lough, N. Ireland. Reconnaisance over a wider area to the south-west is consistent with the hypothesis that this steep plunge is due to the upward push exerted during the emplacement of the Newry Granodiorite. A near surface extension of the intrusion towards the east-north-east is inferred.

Research paper thumbnail of Excessive thickening of the cortical layer in graptolites

Proceedings of the Yorkshire Geological Society, Nov 1, 2011

SUMMARY A number of graptolites with thickened periderm, both dendroids and graptoloids, have bee... more SUMMARY A number of graptolites with thickened periderm, both dendroids and graptoloids, have been examined with the SEM. The thickening is by the deposition of layers of ectocortical tissue, clearly as bandages in the graptoloids. In Colonograptus colonus ...

Research paper thumbnail of Probable orthocone skip and roll marks from the Aberystwyth Grits

Geological Magazine, 1974

SummarySkip and roll marks, probably the impressions of orthocones, are described from the Aberys... more SummarySkip and roll marks, probably the impressions of orthocones, are described from the Aberystwyth Grits (Lower Silurian, mid-Wales).

Research paper thumbnail of The density of graptoloid skeletal tissue, and its implication for the volume and density of the soft tissue

Lethaia, Apr 1, 1987

ABSTRACT It has been proposed by many authors that a mechanism is necessary to achieve neutral bu... more ABSTRACT It has been proposed by many authors that a mechanism is necessary to achieve neutral buoyancy in graptoloids. Calculations are given to show the range of densities needed for both soft and skeletal tissues to achieve this, and it is concluded that a large volume of soft tissue, containing low density fats, is the most likely mechanism. This is not readily compatible with the rhabdopleuran model of the graptolite mid.

Research paper thumbnail of The role of extrathecal tissue in the construction and functioning of some Ordovician and Silurian retiolitid graptoloids

Bulletin of The Geological Society of Denmark, Jun 1, 1987

Research paper thumbnail of Retiolite nomenclature and relationships

Journal of the Geological Society, Jul 1, 1990

... Retiolite nomenclature and relationships DEB BATES Institute of Earth Studies, University Col... more ... Retiolite nomenclature and relationships DEB BATES Institute of Earth Studies, University College of Wales, Aberystwyth, Dyfed SY23 3DB, UK ... For Bulman this cast doubt on the unity of the group, although he did unite them within the single family. Rickards et al. ...

Research paper thumbnail of The structure of the Lower Palaeozoic rocks of Anglesey, with special reference to faulting

Geological Journal, Apr 30, 2007

The principal structures of the Lower Palaeozoic rocks of Angelsey are described. Tight folding, ... more The principal structures of the Lower Palaeozoic rocks of Angelsey are described. Tight folding, with variably developed slaty cleavage and a first phase of reverse faulting, took place probably in late Silurian times, along axes which are parallel to pre‐Cambrian foliation trends. A second phase of reverse faulting followed basic dyke intrusion and was succeeded by normal faulting and mineralization. Joint production was a comparatively late feature. A technique for analysing fault data, in terms of stress axes, is outlined and applied to faulting within the Lower Palaeozoic rocks.

Research paper thumbnail of The Stratigraphy of the Ordovician rocks of Anglesey

Geological Journal, Apr 30, 2007

Arenig sandstones, grits and conglomerates rest unconformably on pre‐Cambrian rocks (the Mona Com... more Arenig sandstones, grits and conglomerates rest unconformably on pre‐Cambrian rocks (the Mona Complex) and are of variable thickness and facies. Higher Arenig and Llanvirn shales, grits, conglomerates, shaly breccias and ironstones are related to contemporaneous fault movements, with abundant slump structures and rare turbidites. A pre‐Caradoc break in sedimentation was followed by deposition of shales, cherty shales, sandstones, breccias and conglomerates on Llanvirn, Arenig and pre‐Cambrian rocks. The Carmel Head Thrust acted as a major line controlling sedimentation, with upthrow to the north. Lower Silurian graptolitic shales at Parys Mountain rest on an acid volcanic group of Caradoc (?) age.