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Los restos de asterozoos son sumamente escasos en el Ordovícico Medio y Superior del suroeste de Europa, si bien la auténtica diversidad de estos equinodermos está largamente enmascarada por su dificultad de fosilización. En este trabajo se presenta la segunda localidad centroibérica donde se registra el ofiuroideo Palaeura hispanica Smith, descubierto por primera vez en el sinclinal de Algodor- Milagro en los Montes de Toledo, y que ahora se identifica en el sinclinal del Guadarranque en las Villuercas. Se trata de un ejemplar completo conservado por su cara dorsal, que muestra la región central del disco erosionada dejando ver las placas orales. Uno de los brazos se halla torsionado, con su extremo ventral vuelto hacia arriba. La conformación de los brazos de P. neglecta Schuchert (Darriwiliense medio de Bohemia y el oeste de Inglaterra) presenta suficientes diferencias con P. hispanica (Darriwiliense medio de la Zona Centroibérica), como para considerar a ambos taxones como especies distintas, en lugar de subespecies geográficas. El ejemplar estudiado se expone en el Centro de Interpretación del Fósil de Navatrasierra, dependiente del Geoparque extremeño Villuercas-Ibores- Jara Fossil asterozoans are extremely rare in the Middle and Upper Ordovician of southwestern Europe, especially because they disarticulate rapidly after death and have a lower potential of fossilization. This paper presents the second record of Palaeura hispanica Smith in the Central Iberian Zone. This ophiuroid was first discovered in the Algodor-Milagro syncline in the Toledo Mountains, and is now characterized in the Guadarranque syncline in Las Villuercas. The single described specimen is preserved by its dorsal face, with the eroded central region of the disc showing the oral plates. One of the arms is turned up, showing details of its ventral surface. Plates from the arms of P. neglecta Schuchert (Middle Darriwilian of Bohemia and western England) show differences with P. hispanica (Middle Darriwilian of the Central Iberian Zone), suggesting they are different species instead of geographical subspecies. The specimen studied is currently exhibited at the Interpretation Center of the Fossil of Navatrasierra, belonging to the Villuercas-Ibores-Jara UNESCO Global Geopark (Extremadura, west of Spain)

Se presentan las asociaciones paleontológicas identificadas en dos localidades situadas en el término de Hinojosa del Duque (Córdoba), en afloramientos del Silúrico correspondientes a antiguas explotaciones a cielo abierto. Los fósiles de la mina Las Angosturas están preservados en calizas arcillosas e incluyen variados nautiloideos ortoconos, bivalvos, escifocrinoideos, filocáridos, ostrácodos y raros graptolitos, estos últimos de probable edad Ludfordiense medio (Biozona de Neocucullograptus kozlowskii). Los fósiles de la Mina Luisa proceden de nódulos en pizarras, conteniendo también nautiloideos ortoconos, bivalvos, filocáridos, ostrácodos y raros graptolitos y poríferos, en ausencia de escifocrinoideos o de especies que puedan aportar precisiones dentro del rango Ludlow-Pridoli. Las biofacies presentes en las localidades estudiadas se correlacionan con otras áreas del Dominio Obejo-Valsequillo y con la Zona de Ossa Morena, siendo muy distintas de los materiales y faunas coetáneos de la Zona Centroibérica meridional. Entre los resultados taxonómicos, los ostrácodos Sineruga insolita y Silurocypridina calva se identifican por vez primera en España, así como el nautiloideo Akrosphaerorthoceras gregale o el género Warneticaris (filocárido). Algunos bivalvos atribuidos comúnmente al Pridoli podrían tener su registro más antiguo en horizontes del Ludlow, si bien la confirmación queda supeditada al hallazgo de graptolitos más completos y en mejor estado de conservación Fossiliferous upper Silurian strata have been identified in two abandoned open-pit mines within the municipality of Hinojosa del Duque (province of Cordoba). The fossils from Las Angosturas mine are preserved in argillaceous limestones and include orthocone nautiloids, bivalves, scyphocrinoids, phyllocarids, ostracods and rare graptolites, the latter of probably middle Ludfordian age (Neocucullograptus kozlowskii Biozone). The fossils from Mina Luisa come from nodules occurring in sericitic shales, and the assemblage also includes orthocone nautiloids, bivalves, phyllocarids, ostracods and rare graptolites and porifera, but no species (scyphocrinoid or other) can provide precision within the Ludlow-Pridoli range. Fossil records are correlatable with other areas of the Obejo-Valsequillo Domain and the Ossa-Morena Zone, being very different from the contemporary materials and faunas of the southern Central Iberian Zone. Among the taxonomic results, the entomozooid ostracods Sineruga insolita and Silurocypridina calva are identified for the first time in Spain, as well as the nautiloid Akrosphaerorthoceras gregale or the phyllocarid genus Warneticaris. Some typical ‘Pridoli’ bivalves of the peri-Gondwanan area may present here their oldest occurrence in Ludlow horizons, although confirmation of this hypothesis requires the finding of more complete and well-preserved graptolites

Los restos de asterozoos son sumamente escasos en el Ordovícico Medio y Superior del suroeste de Europa, si bien la auténtica diversidad de estos equinodermos está largamente enmascarada por su dificultad de fosilización. En este trabajo se presenta la segunda localidad centroibérica donde se registra el ofiuroideo Palaeura hispanica Smith, descubierto por primera vez en el sinclinal de Algodor- Milagro en los Montes de Toledo, y que ahora se identifica en el sinclinal del Guadarranque en las Villuercas. Se trata de un ejemplar completo conservado por su cara dorsal, que muestra la región central del disco erosionada dejando ver las placas orales. Uno de los brazos se halla torsionado, con su extremo ventral vuelto hacia arriba. La conformación de los brazos de P. neglecta Schuchert (Darriwiliense medio de Bohemia y el oeste de Inglaterra) presenta suficientes diferencias con P. hispanica (Darriwiliense medio de la Zona Centroibérica), como para considerar a ambos taxones como especies distintas, en lugar de subespecies geográficas. El ejemplar estudiado se expone en el Centro de Interpretación del Fósil de Navatrasierra, dependiente del Geoparque extremeño Villuercas-Ibores- Jara, Fossil asterozoans are extremely rare in the Middle and Upper Ordovician of southwestern Europe, especially because they disarticulate rapidly after death and have a lower potential of fossilization. This paper presents the second record of Palaeura hispanica Smith in the Central Iberian Zone. This ophiuroid was first discovered in the Algodor-Milagro syncline in the Toledo Mountains, and is now characterized in the Guadarranque syncline in Las Villuercas. The single described specimen is preserved by its dorsal face, with the eroded central region of the disc showing the oral plates. One of the arms is turned up, showing details of its ventral surface. Plates from the arms of P. neglecta Schuchert (Middle Darriwilian of Bohemia and western England) show differences with P. hispanica (Middle Darriwilian of the Central Iberian Zone), suggesting they are different species instead of geographical subspecies. The specimen studied is currently exhibited at the Interpretation Center of the Fossil of Navatrasierra, belonging to the Villuercas-Ibores-Jara UNESCO Global Geopark (Extremadura, west of Spain)

[ES] Los graptolitos silúricos de la Zona Centroibérica suelen conservarse aplastados en pizarras negras, pero en algunos yacimientos los rabdosomas pueden retener parte de su relieve original o conservarse incluso en tres dimensiones. La mayoría de las veces existe una piritización temprana de los rabdosomas por la acción de bacterias sulforreductoras en ambiente anóxico, a la que se suma la génesis de nódulos. La alteración posterior de la pirita deja los graptolitos en forma de moldes, que pueden ser estudiados mediante vaciados en látex. Otros fenómenos de piritización multifásica en sedimentos gruesos conducen a la formación de nódulos de pirita que incluyen en su interior graptolitos huecos y en tres dimensiones, con el peridermo replicado delicadamente en óxidos de hierro. En otras ocasiones, los graptolitos preservados en nódulos generados en sedimentos pelágicos incluyen el recrecimiento de fosfatos sobre el peridermo de los graptolitos, que llegan a conservarse huecos y con estructuras de rellenos geopetales. Finalmente, se presenta el único caso de calizas con graptolitos conocido en el Silúrico centroibérico., [EN] Silurian graptolites form the Central-Iberian Zone are often preserved as flattened moulds in black shales, but in some cases rhabdosomes can maintain a part of its original relief, and even can appear three-dimensionally preserved. The majority of these cases can be related to an early pyritisation of the periderm favoured by bacterial activity under anoxic conditions, which also led to the genesis of nodules on the same beds. Further oxidation and dissapearance of iron minerals limited the preservation of graptolites to external moulds, that can be studied through latex casts. A different way of preservation of 3-D graptolites occurs in coarse sandstone that enhanced multiphase pyritisation fenomena, where ferruginous nodules enclosing rhabdosomes reveal that the framboidal pyrite that mineralized the periderm during very early diagenesis was remarkably resilient not only to subsequent deformation, but also to the differential weathering of the massive overpyrite that constitute the nodules. The pyritised graptolite periderm was finally replicated by iron-oxides with a minor proportion of phyllosilicates. The occurrence of “hollow” graptolites is also known from silico-phosphatic nodules, where the organic periderm was finely replicated by phosphatic overgrowths that coated the inner and outer surfaces of the rhabdosome. Occasional pseudostalactites of phosphatic minerals and colloidal silica partially occupied the empty spaces. Graptolite internal moulds occurring in limestone are very rare and are restricted to a single locality within the studied region.

The discovery of Didymograptus (Didymograptus) artus Elles and Wood in the Ordovician section of the Vidrias Cape (Atlantic coast of Spain), constitutes the first record of early Oretanian (= mid Darriwilian) rocks in the Cantabrian Zone of the Iberian Massif. The fossil locality lies in a shaly intercalation towards the middle part of an easternmost equivalent of the «Sabugo Quartzite» of the Navia Domain (West Asturian-Leonese Zone), so far unknown in the reference section for the Ordovician of the Cantabrian Zone of the nearby Peñas Cape. Correlations of the studied strata by previous authors are also reviewed, and the existence of a fault is suggested to occur between the «Peñas» and «Vidrias» members of the Luarca Formation on the famous section of the Peñas Cape

4 páginas, 2 figuras.-- Trabajo presentado en la 44ª Sesión Científica, Jaén, 2008., Lower and Middle Ordovician rocks outcropping in the Cabañeros National Park (Central Iberian Zone) are being explored within a mapping project aimed at identifying geosites representative of the geological and paleontological heritage on this natural area. Ongoing field-work has led to the discovery of three fossil localities that bring out significant paleontological data relevant to the whole Iberian Massif. The oldest comes from the upper part of the Armorican Quartzite Fm. (Floian/middle Arenigian) and is a large ichnofossil identified as Tumblagoodichnus? isp., which probably represents a shallow burrow filled by collapse of sand from above, and dug as a temporary refuge by a large arthropod. The trace is 45 cm wide, much bigger than the large arthropod traces previously reported from the Iberian Ordovician (rare Cruziana reach up to 26 cm in width). The second fossil locality lies towards the middle part of the overlying Marjaliza Beds (Dapingian to lower Darriwilian/middle-upper Arenigian) and is represented by a thick coquina of paleotaxodont and paleoheterodont bivalves, apparently formed due to a catastrophic event (an exceptional storm?) that transported and entombed en masse millions of individuals now preserved as complete specimens with closed valves. This local abundance strongly contrasts with the scarcity of Arenigian bivalves preserved in the Cruziana sandstone facies of SW Europe. Finally, the youngest locality is a rich fossiliferous bed of lower Oretanian (Darriwilian) age recorded in the Navas de Estena Shales, where the brachiopod genus Eodalmanella (Ranorthidae) makes its second European occurrence and reinforces the Ibero-Bohemian paleobiogeographic affinities., Acción Estratégica 56/2006 de la Red de Parques Nacionales. Proyecto PATRIORSI, CGL2006-07628/BTE. Proyecto PICG 503 del Programa Internacional de Geociencias (IUGS-UNESCO) y las actividades del Grupo de Investigación Precámbrico y Paleozoico Perigondwánico de la Universidad Complutense de Madrid.

Lower and Middle Ordovician rocks outcropping in the Cabañeros National Park (Central Iberian Zone) are being explored within a mapping project aimed at identifying geosites representative of the geological and paleontological heritage on this natural area. Ongoing field-work has led to the discovery of three fossil localities that bring out significant paleontological data relevant to the whole Iberian Massif. The oldest comes from the upper part of the Armorican Quartzite Fm. (Floian/middle Arenigian) and is a large ichnofossil identified as Tumblagoodichnus? isp., which probably represents a shallow burrow filled by collapse of sand from above, and dug as a temporary refuge by a large arthropod. The trace is 45 cm wide, much bigger than the large arthropod traces previously reported from the Iberian Ordovician (rare Cruziana reach up to 26 cm in width). The second fossil locality lies towards the middle part of the overlying Marjaliza Beds (Dapingian to lower Darriwilian/middle-upper Arenigian) and is represented by a thick coquina of paleotaxodont and paleoheterodont bivalves, apparently formed due to a catastrophic event (an exceptional storm?) that transported and entombed en masse millions of individuals now preserved as complete specimens with closed valves. This local abundance strongly contrasts with the scarcity of Arenigian bivalves preserved in the Cruziana sandstone facies of SW Europe. Finally, the youngest locality is a rich fossiliferous bed of lower Oretanian (Darriwilian) age recorded in the Navas de Estena Shales, where the brachiopod genus Eodalmanella (Ranorthidae) makes its second European occurrence and reinforces the Ibero-Bohemian paleobiogeographic affinities

Preliminary studies of some stratigraphic sections spanning the Ordovician-Silurian boundary in the southern Cantabrian Zone (Iberian Massif, NW Spain) demonstrate the existence of a record of Hirnantian glaciomarine diamictites and shallow-water quartzites in at least three localities, situated in the Bodón nappe. These rocks, evidenced for the first time in the Cantabrian Zone, are probably related to the infilling of a paleorelief, scoured in the Barrios Formation during the Late Ordovician glaciation. The occurrence of an ubiquitous quartzite unit, generally related to the Ordovician-Silurian boundary in most parts of northern Gondwana, is now extended to the outcrops here analyzed. The Hirnantian quarzite probably occurs in additional areas of the Bodón and Correcilla nappes, where its location and significance might be underestimated, and described as the uppermost part of the Barrios Formation (Middle Cambrian to Arenigian). The same quartzite is probably recognized in the areas with volcanic necks within the Barrios Formation, and also in its stratotype, in which a latest Ordovician/earliest Silurian quartzite overlies unconformably on Middle Ordovician shales

[ES] La revisión completa de más de un centenar de localidades fosilíferas del Ordovícico Medio situadas en el noroeste del Macizo Hespérico, muestra que el depósito de las pizarras y limolitas oscuras (Formación Luarca y equivalentes), que siguen a las cuarcitas del Arenig, no fue tan uniforme como se consideraba hasta ahora. Las pizarras se sedimentaron esencialmente durante el Oretaniense en la Zona Asturoccidental-Leonesa y en la parte septentrional de la Zona Centroibérica (Dominio del Ollo de Sapo), donde el techo de la unidad se sitúa muy próximo al límite Oretaniense / Dobrotiviense, sin existir ningún yacimiento paleontológico de probada edad dobrotiviense (= "Llandeilo inferior" en sentido clásico). En la Zona Cantábrica, la sedimentación arcillosa se inicia en el Oretaniense superior tardío y prosigue durante el Dobrotiviense. Para el conjunto del área estudiada se caracterizan, o proponen, diversas lagunas estratigráficas de alcance local o regional, y se discuten las circunstancias paleogeográficas generadas por las hipótesis más recientes, que son contrastadas a la luz de los nuevos datos paleoecológicos y paleobiogeográficos. Éstos indican que la sedimentación tuvo lugar en áreas externas y abiertas de la plataforma, relativamente más profundas que en la región surcentroibérica, con áreas de surco donde ingresan elementos mesopelágicos. Desde el punto de vista paleontológico, se reconocieron un total de 97 formas distintas (67 especies presentes en el Oretaniense y 45 en el Dobrotiviense), entre las que destaca la primera aparición conocida de determinadas especies de trilobites y ostrácodos, el registro más moderno de otros, y algunos taxones en común con Avalonia y Baltica, desconocidos hasta el presente en otras áreas del suroeste de Europa, [EN] A complete review of more than one hundred Middle Ordovician fossil localities, distributed within the north western part of the Hesperian Massif, shows that the sedimentation of the dark shales (Luarca Fo rmation and equivalents) that overlie Arenig quartzites with Cruziana (the 'Armorican Quartzite' facies) was not as uniform as it has been supposed for the whole NW Spain. These shales were mainly deposited during the Oretanian in the West Asturian-Leonese Zone and in nort h e rn Central-Iberian Zone (Domain of the Ollo de Sapo Antiform). In these zones, the top of the unit is close to the Oretanian/Dobrotivian boundary, without any fossils with proved Dobrotivian age., Este trabajo ha sido financiado con cargo al Proyecto PB94-1330 de la DGESEIC ["Investigaciones estratigráficas y paleontológicas en las formaciones Luarca y Sueve (Ordovícico Inferior y Medio de Asturias y León)]", y constituye una contribución a los proyectos nº 410 del PICG (IUGS-UNESCO)e "Iberia" de EURO P ROBE (European Science Foundation). La participación de J.C. Gutiérrez-Marco y de I. Rábano se inscribe igualmente en el Proyecto PB96-0839 (Bioestratigrafía de alta resolución y litorradiometría en el Ordovícico Medio-Silúrico de España) de la DGESEIC (Ministerio de Educación y Cultura). La investigación museográfica en colecciones antiguas, forma parte del Proyecto 06/0006/98 ("Investigación y catalogación de colecciones paleontológicas singulares del Museo Geominero"), financiado por la Comunidad de Madrid.

The holotype of''Echinosphaerites'' murchisoni Verneuil and Barrande 1855 is reviewed, and proposed as the type species of Oretanocalix gen. nov. The new genus is characterised by an elongate theca of medium size, that aborally shows a pair of long and prominent parietal septa interpreted as mesenterical; mouth narrow and elongate, with five very short ambulacra, the anterior comparatively reduced, ending in a set of few brachiole facets. The presence of a 2-1-2 ambulacraI system with an atrophied A-ambulacrum could denote a simplification leading to the 2-2 pattern of Calix or Phlyctocystis. The new genus ranges from Oretanian to Dobrotivian in age, and is distributed in Central Spain, the Moroccan Anti-Atlas and the French Armorican Massif

24 páginas, 4 figuras, 2 láminas, 1 tabla., [EN] New palaeontological data from Upper Ordovician formations of NW Spain (Caurel-Peñalba and Truchas synclines) are documented. The «Trigal limestones» of the Casaio Formation, the La Aquiana Formation and calcareous pebbles of the Rozadais Formation have yielded conodont assemblages indicating the Ashgillian Anzorphognathus ordovicicus Biozone. Scabbardella altipes (Henningsmoen), Panderodus gracilis (Branson & Mehl), Anzorplzognathus ordovicicus Branson & Mehl, Amorphogizatlzus sp., Sagittodontiíza robusta Knüpfer, Sagittodontina? sp., Icriodella sp. and Hamarodus europaeus (Serpagli) have been identified and described. Stratigraphic correlations between the different structural units are discussed, as well as the regional context of the Upper Ordovician sedimentation. According to a new model which conciliates the local geotectonic setting with the global paleoclimatic events, the Rozadais Formation underwent a glaciomarine influence during the Hirnantian, and is clearly younger in age that other Ashgill units which consist or include pre-Hirnantian limestones (La Aquiana and Casaio formations)., [ES] Se presentan las asociaciones de conodontos ordovícicos registradas en las «calizas del Trigal» de la Formación Casaio, en la Formación La Aquiana y en los cantos calcáreos englobados en la Formación Rozadais, pertenecientes a afloramientos del sinclinorio de Truchas (norte de la Zona Centroibérica) y del sinclinal del Caurel-Peñalba (sur de la Zona Asturoccidental-leonesa). Las formas identificadas son Scabbardella altipes (Henningsmoen), Paizdei~odus gracilis (Branson y Mehl), Amorphognathus ordovicicus Branson y Mehl, Anzorphognathus sp., Sagittodoiztiiza robusta Knüpfer, Sagittodontina? sp., Icriodella sp. y Hanzarodus europaeus (Serpagli), que corresponden a la Biozona de Aínorphognathus ordovicicus del Ashgill y se describen e ilustran en el apartado sistemático. En función de estos datos y sus circunstancias estratigráficas, se propone una correlación general de las unidades del Ordovícico Superior de la región, presentándose un nuevo modelo que armoniza el marco geotectónico local con los eventos globales del Ashgill comunes a la región nord-gondwaniense. En este sentido, se considera un influjo glaciomarino para la Formación Rozadais (Hirnantiense), cuyo depósito no sería coetáneo con las unidades calcáreas pre-Hirnantienses (Trigal y La Aquiana)., Este trabajo se inscribe en los proyectos PB94-1330 y PB96-0839 de la DGES, y sus resultados son también una contribución al Proyecto 410 del PICG (IUGS-UNESCO), así como al Proyecto «Iberia» del Programa EUROPROBE (European Science Foundation). La participación del primer autor fue posible gracias a una beca postdoctoral de la Comunidad de Madrid, que lleva por título «Aplicación de Conodontos en bioestratigrafía de alta resolución y geotermometría de materiales ordovícicos y silúricos de España» (1998-1999).

The holotype of''Echinosphaerites'' murchisoni Verneuil and Barrande 1855 is reviewed, and proposed as the type species of Oretanocalix gen. nov. The new genus is characterised by an elongate theca of medium size, that aborally shows a pair of long and prominent parietal septa interpreted as mesenterical; mouth narrow and elongate, with five very short ambulacra, the anterior comparatively reduced, ending in a set of few brachiole facets. The presence of a 2-1-2 ambulacraI system with an atrophied A-ambulacrum could denote a simplification leading to the 2-2 pattern of Calix or Phlyctocystis. The new genus ranges from Oretanian to Dobrotivian in age, and is distributed in Central Spain, the Moroccan Anti-Atlas and the French Armorican Massif

A typical example of the Helminthopsis ichnogulld formed by deep deposit-feeder tiers is presented from an Upper Ordovician shallow marine succession in Central Spain. The monospecific ichnoassociation is composed by Helminthopsis abeli Ksiazkiewicz, massively recorded from a single bed within a sillciclastic alternation with some storm influence ofCaradoc age, in the lower part of the "Bancos Mixtos" Formation, south of the town of Torrenueva (Province of Ciudad Real)

A typical example of the Helminthopsis ichnogulld formed by deep deposit-feeder tiers is presented from an Upper Ordovician shallow marine succession in Central Spain. The monospecific ichnoassociation is composed by Helminthopsis abeli Ksiazkiewicz, massively recorded from a single bed within a sillciclastic alternation with some storm influence ofCaradoc age, in the lower part of the "Bancos Mixtos" Formation, south of the town of Torrenueva (Province of Ciudad Real)

The type specimen ofthe Lower Cambrian (Bilbilian) trilobite «Ellipsocephalus pradoanus» Verneuil & Barrande, 1855 is redescribed and illustrated. It is stored in the Verneuil collection ofthe Claude-Bernard University at Lyon (France). By means of the cranidial characteristics it has been doubtfully related with the genus Realaspis, and the poor preservation of the lectotype of R. ? pradoanus supports the restriction of the species to this unique specimen

Some scarce and bad preserved bivalves have been described from few localities lying at the upper part of the Armorican quartzite facies in Central Spain. Middle Arenig faunas include two palaeotaxodont forms (Praenucula oehlerti and Cardiolaria sp.), and two different palaeoheterodonts (Modiolopsis sp. and ?Actinodontoida indet.). Previous reports of other Arenig bivalves, especially actinodontoids, from coeval quartzites of northwestern, Central and northeastern Spain, as well as from Central Portugal, have been also briefly examined. The Iberian faunas show close affinities with the well known Arenig assemblages from the «Grès armoricain» of Western France, and add new data for the scenic reconstruction of the Lower Ordovician bivalve radiations on the northwestern Gondwanan shelves

The type specimen ofthe Lower Cambrian (Bilbilian) trilobite «Ellipsocephalus pradoanus» Verneuil & Barrande, 1855 is redescribed and illustrated. It is stored in the Verneuil collection ofthe Claude-Bernard University at Lyon (France). By means of the cranidial characteristics it has been doubtfully related with the genus Realaspis, and the poor preservation of the lectotype of R. ? pradoanus supports the restriction of the species to this unique specimen

3 páginas, 2 figuras.-- Trabajo presentado en la 21ª Sesión Científica, Huelva 1996., Two new fossil localities yielding graptolites of the lundgreni and leíntwardinensís biozones (early Homerian and basal Ludfordian, respectively) are studied from the Alange region, which lies on the southernmost part of the Central Iberian Zone. Previous mentions to graptolites from a nearby outcrop were also reviewed and the orignal specimens reassigned to some earlier horizons in the Wenlock. All these data confirm the presence of Silurian rocks over a region very imprecisely known in terms of Paleozoic sedimentary geology and paleogeography., Este trabajo es una contribución al Proyecto 351 del PICG (IUGS-UNESCO), y los estudios de campo fueron financiados por el Proyecto AMB92-1037-C02-01 de la DGICYT.

The first Silurian graptolites from NW Spain were discovered South of Brazuelo de Pradorrey (province of León) by Casiano de Prado in 1855. The locality lies in the core of the Castrillo syndine, where the Silurian succession is composed by a lower unit of ?Rhuddanian-Aeronian sandstones, gradually passing to an upper unit of black graptolitic shales. Aeronian graptolites (?D. triangulatus and D. convolutus biozones) were reported from the top of the sandy formation and from the transitional beds in the lower half of the overlying unit. The Brazuelo locality corresponds to the younger black shales, and includes three sucessive horizons with Telychian graptolites. The first one represents the upper part of the R. linnaei Biozone, followed up in the section by a second assemblage, which probably belongs to the M. griestoniensis 3¡ozone, and finally, by a third horizon also representative of the M. griestonensis or even the T. tulibergi Biozone. Craptolite assemblages are poor and bad preserved, but include some species of high palaeobiogeographic and palaeoenvironmental significance, as for instance Metaclimacograptus cf. asejradi Legrand or Paraclimacograptus? flamandi (Legrand), typical of shallow sapropelitic facies in peri- and intracratonic Gondwanan basins

The first Silurian graptolites from NW Spain were discovered South of Brazuelo de Pradorrey (province of León) by Casiano de Prado in 1855. The locality lies in the core of the Castrillo syndine, where the Silurian succession is composed by a lower unit of ?Rhuddanian-Aeronian sandstones, gradually passing to an upper unit of black graptolitic shales. Aeronian graptolites (?D. triangulatus and D. convolutus biozones) were reported from the top of the sandy formation and from the transitional beds in the lower half of the overlying unit. The Brazuelo locality corresponds to the younger black shales, and includes three sucessive horizons with Telychian graptolites. The first one represents the upper part of the R. linnaei Biozone, followed up in the section by a second assemblage, which probably belongs to the M. griestoniensis 3¡ozone, and finally, by a third horizon also representative of the M. griestonensis or even the T. tulibergi Biozone. Craptolite assemblages are poor and bad preserved, but include some species of high palaeobiogeographic and palaeoenvironmental significance, as for instance Metaclimacograptus cf. asejradi Legrand or Paraclimacograptus? flamandi (Legrand), typical of shallow sapropelitic facies in peri- and intracratonic Gondwanan basins

The first record outside Bohemia of the recumbent diploporid Aristocystites metroi is presented. It consists of a remarkable specimen from the Dobrotivian shales of CaIzada c/e Calatrava (Central Iberian Zone). The Spanish occurrence of the species is markedly older (Dobrotivian: Middle Ordovician) than in Bohemia (Zahoranlan and Kosovian; Upper Ordovician). Our specimen derives also from much shallower environments with respect to the type material

The first record outside Bohemia of the recumbent diploporid Aristocystites metroi is presented. It consists of a remarkable specimen from the Dobrotivian shales of CaIzada c/e Calatrava (Central Iberian Zone). The Spanish occurrence of the species is markedly older (Dobrotivian: Middle Ordovician) than in Bohemia (Zahoranlan and Kosovian; Upper Ordovician). Our specimen derives also from much shallower environments with respect to the type material

Upper Ordovician rocks have been characterized for the first time in the Cantabrian Zone of the Hesperian Massif. The sequence consists of a lower siliciclastic unit of Caradoc-(‘basal Ashgill age developed as an alternation of shales, siltstones and sandstones, overlain by an upper unit of fossiliferous limestones with marly intercalations, of pre-Hirnantian (mainly Cautleyan-Rawtheyan) age. Ashgill fossils are fairly abundant in the limestone unit, and there have been identified brachiopods of the «Nicolella fauna», echinoderms of the «Heliocrinites fauna» and trilobites of the Qvalocephalus biofacies

Se presenta el hallazgo de un bellerofóntido del Ordovicico medio de los Montes de Toledo (Zona Centroibérica), que presenta diversos depósitos secundarios en la superficie externa de la concha, interpretados como perinductura, inductura y coinductura. Tales depósitos se consideraban característicos de ciertos gasterópodos devónico-pérmicos (Euphemitidae), por lo que su primer registro entre los sinuítidos ordovícicos plantea unas relaciones hlogenéticas inéditas con un modo de secreción similar en ambos grupos y, secundariamente, ello representa un nuevo argumento en favor de la clasificación de los Sinuitidae entre los gasterópodos

Fossiliferous shales of the Luarca Formation are identified for the first time in the southern part of the Pliegues y Mantos domain of the western Cantabrian Zone. The outcrop consists of 10,6 m of dark shales and micaceous silts tones, tectonically intercalated between the La Matosa (Middle and Upper Cambrian) and Tanes (Arenig) members of the Barrios Formation, close to the classical section of this unit. The occurrence of a diverse assemblage of trilobites, graptolites, ostracods, brachiopods, echinoderms, molluscs and some acritarchs and chitinozoans confirms a Middle Ordovician age for the shales, whereas the age of the top of the Barrios Formation does not exceed the Arenig

A new continuous section with Aeronian to lower Telychian graptolites is described near Corral de Calatrava (province of Ciudad Real). The transition between the «Criadero Quartzite» and the overlying black shales is detailed. The section is correlated with another similar sucessions around the Ordovician/ Silurian boundary in the southern part of the Central Iberian Zone, and chronostratigraphic aspects are briefly analyzed and discussed. The sedimentation of the «Criadero Quartzite» took place during Rhuddanian to late Aeronian times; a minor hiatus was developed at the upper limit with the graptolitic black shales. The base of the latter is not older than the palmeus sub-biozone of the early Telychian

Two new fossil localities yielding graptolites of the, (undgreni and leintwardinensis biozones (early Homerian and basal Lùdfordiàn, respectively) are studied from the Al an gè region, which lies on the southernmost part of the Central Iberian Zone, Previous mentions to graptolites from a nearby outcrop were also reviewed and the original specimens reassigned to some earlier horizons in the Wenjock AH these data confirm the presence of Silurian rocks over a region very imprecisely known in terms of Paleozoic sedimentary geology and paleogeograppy

Se presenta el hallazgo de un bellerofóntido del Ordovicico medio de los Montes de Toledo (Zona Centroibérica), que presenta diversos depósitos secundarios en la superficie externa de la concha, interpretados como perinductura, inductura y coinductura. Tales depósitos se consideraban característicos de ciertos gasterópodos devónico-pérmicos (Euphemitidae), por lo que su primer registro entre los sinuítidos ordovícicos plantea unas relaciones hlogenéticas inéditas con un modo de secreción similar en ambos grupos y, secundariamente, ello representa un nuevo argumento en favor de la clasificación de los Sinuitidae entre los gasterópodos

Torrubia (1754) was the first to describe the presence of nodules in the Silurian black shales cropping out in the old tile works near El Pobo de Dueñas in the province of Guadalajara. He called them «geode-stones» reminiscent to «little cakes and diceboxes», considering them as petrefacts of nonorgan ic origin. The presence of nodules in Silurian graptolite facies in several i be rían localities is also briefly examined, and the diverse popular interpretations of these structures in the country are also annotated (i.e. «moorish heads», mammut-coprdlites, turtles or even «copro/ithus neanderthalensis»

7 páginas, 1 figura., [EN] Trilobite and mollusc remains from the Luarca Slates Formation, SO Ribadeo (Lugo province), collected more than 150 years ago by SCHULZ, have been identified as Calymenidae indet, and Endocerida indet. They belong to his Galician petrologic collection of 1835, actually preserved at the GeoMinero Museum of Madrid, and constitute the first documented Galician fossils from a chronological point of view., [ES] Se estudian los restos de trilobites y moluscos descubiertos hace más de 150 años por SCHULZ en los afloramientos de la Formación de Pizarras de Luarca al SO de Ribadeo (Lugo), a través del material original de su trabajo de 1835. Este se conserva en el Museo GeoMinero de Madrid, correspondiendo la formas revisadas (Calymenidade indet. y Endocerida indet.) a los primeros fósiles documentados en Galicia desde el punto de vista cronológico.