Central Newfoundland Research Articles

A reexamination of moose damage to balsam fir–white birch forests in central Newfoundland: 27 years later

A 1960 study from central Newfoundland suggested that moose (Alcesalces L.) would: (i) reduce the commercial value of second-growth forests of central Newfoundland by excessive damage to balsam fir (Abiesbalsamea (L.) Mill.); (ii) eliminate white birch (Betulapapyrifera Marsh.) from the forest canopy; (iii) alter conifer species composition; and (iv) reduce the carrying capacity of the area for moose. We resurveyed the original study areas in 1987. Our data suggest that moose have altered species composition in favour of white spruce (Piceaglauca (Moench) Voss) and black spruce (Piceamariana (Mill.) B.S.P.) on some sites and have reduced the mean height of balsam fir trees. White birch was generally absent from the canopy. However, contrary to the 1960 prediction, moose appear to have had a positive influence on forest growth by thinning most areas to stem densities comparable with those of precommercially thinned stands. Data from this study were compared with a general model of the influence of moose on balsam fir forests developed for Isle Royale, Michigan. Our data supported two predictions from Isle Royale: moose damage was highest at low balsam fir densities and at highest moose densities. Our results contradicted a third prediction, that height growth was greater in high density stands of saplings. Also, unlike at Isle Royale, despite heavy browsing pressure for extended periods, balsam fir will continue to dominate central Newfoundland forests.

The Pipestone Pond Complex, central Newfoundland: complex magmatism in an eastern Dunnage Zone ophiolite

Ophiolitic rocks are preserved in both the Notre Dame and Exploits subzones in the Dunnage Zone of the Newfoundland Appalachians. Ophiolites in the Exploits Subzone are generally less well preserved and exposed than their Notre Dame Subzone counterparts and, consequently, have received less attention in the literature.The Pipestone Pond Complex is an Exploits Subzone ophiolitic sequence, which outcrops on the western side of a structural window through the Exploits Subzone into the underlying Gander Zone. It includes a basal harzburgite, which passes upwards into a cumulate pyroxenite and gabbro sequence, and thence into isotropic gabbro intruded by pegmatitic gabbro, diabase, and plagiogranite. There is no sheeted dyke unit. Pillow lava occurs at the top of the sequence but is not observed to be in stratigraphic contact with the intrusive rocks. The ophiolitic rocks are structurally disrupted and no single cross section traverses the complete ophiolitic stratigraphy.Although the stratigraphic sequence of the Pipestone Pond Complex is relatively straightforward, whole-rock geochemical and Nd/Sm isotopic data provide evidence for a complex magmatic history. The intrusive rocks have εNd(t) ranging from −1.1 to + 4 and geochemical signatures indicating derivation from depleted and refractory mantle sources that were clearly influenced by subduction. Within the intrusive rocks, there are no simple petrogenetic relationships among the gabbros and dykes and trondhjemites. The extrusive rocks, in contrast, have εNd(t) of + 7.3 and geochemical signatures similar to those of normal mid-ocean-ridge basalts. They represent magmatism derived from depleted oceanic mantle, not affected by the subducted slab.The tectonic interpretation of the Pipestone Pond Complex is hampered by a lack of definitive evidence for the relative age of the arc-related plutonic rocks and the non-arc-related extrusive rocks. Two possible interpretations are (i) the initiation of subduction under oceanic crust and (ii) arc rifting. The Pipestone Pond Complex is geologically and geochemically analogous to the Boil Mountain Complex in Maine, and together they may form part of an extensive ophiolitic terrane that was emplaced upon the Gondwanan continental margin prior to its collision with Laurentia.

Early Silurian paleolatitude for central Newfoundland from paleomagnetism of the Wigwam Formation: Reply

Redbeds and minor volcanic rocks of the Early Silurian Wigwam Formation of the Botwood Group were sampled in the Exploits Subzone of the Dunnage Zone of central Newfoundland. At 18 sedimentary and 3 volcanic sites thermal demagnetization isolated a shallow northward (or southward) magnetization (D = 356.0°, I = −16.8°; k = 12.9; α95 = 9.2°; n = 21 site means) after correction for the tilt of bedding. A positive fold test demonstrates that this remanence predates regional Siluro–Devonian folding. A primary age for the remanence is indicated by positive conglomerate tests on volcanic clasts, and reversals correlated with sedimentary stratigraphy. Antiparallel remanence directions at sites of opposite polarity indicate that the primary remanence is not partially overprinted by a secondary component. The Exploits Subzone of the Dunnage Zone is interpreted to have been at low paleolatitudes (8.5°S ± 5°) during the Early Silurian. We reached a similar conclusion for the Notre Dame Subzone of the Dunnage Zone in...

Early Silurian paleolatitude for central Newfoundland from paleomagnetism of the Wigwam Formation: Discussion

Early Silurian paleolatitude for central Newfoundland from paleomagnetism of the Wigwam Formation: Discussion

Tensor CSAMT studies at the Buchans Mine in central Newfoundland

A novel application of the tensor controlled source audio‐magnetotelluric (CSAMT) method was part of a multidisciplinary geophysical study of an existing mine site at Buchans, Newfoundland. The orthogonal components of the horizontal electromagnetic fields used for magnetotelluric and CSAMT interpretation of the earth’s conductivity structure were found to be inappropriate at Buchans because of strong scattering in the electric fields. Instead, the length of the major axes of the electric and magnetic field polarization ellipses and the vertical magnetic field were used as data. The data from two bipole sources demonstrate that the bulk response of the earth in the vicinity of Buchans is predominantly one‐dimensional (1-D). These data were inverted to layered earth models with a first‐order correction for electric field distortions. The parameter space considered during the inversion was contracted substantially by incorporating the vertical magnetic field data and by using depths to interfaces as determined by reflection seismic data. The model resulting from the inversions is essentially a two‐layered earth with an increase in resistivity between 1000–1400 m depth. The contrast in the electrical properties is interpreted to be coincident with the Powerline Fault, a floor thrust of a duplex structure with significant out‐of‐sequence movement. Hence, the thrusting may have caused the emplacement of older fractured, and locally mineralized rocks over younger more competent (resistive) ones.

High School Students' Views About the Nature of Science

This study examined high school students' views of the nature of science. A stratified random sample of 32 students chosen from nine schools in eastern and central Newfoundland were interviewed on an individual basis. The interviews were semi-structured and were administered in general accordance with an interview guide. The transcripts were reduced to a set of individualized conceptual inventories. The frequency of occurrence of each representative statement was tallied and tabulated. A number of general trends were identified. Most students were found to have difficulty establishing the domain of science although many tended to view the practice of science as cumulative. Although the majority of the sample asserted that information was tentative and provisional, they tended to regard factual information in science to be absolute and irrefutable. Scientific theories appeared to be only understood in a naive sense in that most subjects regarded theories as suggested explanations for fairly discrete events as opposed to elaborate interpretive frameworks. In accordance with previously documented evidence (Aikenhead, 1987) many subjects were found to equate the term scientific law with the more common legal usage of the word. Finally, elements of what Nadeau and Desautels (1984) term as naive realism, blissful empiricism, credulous experimentalism and excessive rationalism were found to be quite prevalent in the transcripts.

A vibroseis reflection seismic survey at the Buchans Mine in central Newfoundland

We present results from the first major vibroseis seismic reflection survey at a mine site in North America. It is demonstrated that conventional high‐stack fold reflection seismic techniques can image fault structures associated with volcanogenic massive sulfide bodies, despite the fact that these structures are locally steeply dipping and produce records with low signal‐to‐noise ratios. The new lines were recorded at the locations of two earlier experimental explosive surveys that failed to image many strong reflectors. The principal reasons for the success of the vibroseis experiment were the proper choice of sweep frequencies for maximum signal‐to‐noise ratio, the use of high‐stack fold, and the careful analysis of velocities and statics during processing. A comparison of the new seismic sections with borehole and other geophysical data indicates that the origin of reflections at Buchans can be attributed to various mechanisms including contrasts in lithologies and rock competence and intrusion of diabase sills into pre‐existing fault zones. The best reflections emanate from shallow‐dipping brittle‐ductile thrust fault zones characterized by fault gouge within broader fractured zones. The two seismic lines presented have proven to be a useful and cost‐effective supplement to existing borehole and geophysical data and have provided enough new information on the nature of thrust faulting at the mine to significantly influence current exploration plans.

A geophysical and geochemical interpretation of the configuration of the Mount Peyton complex, central Newfoundland

An integrated geophysical, geological and geochemical study of the Mount Peyton complex in central Newfoundland has provided insight into the surface and subsurface configuration of the feature. The geology, magnetics, gravity, copper, nickel and uranium data enable us to delineate and redefine the lithological boundaries of the complex and develop an appreciation of its possible configuration at depth.
 
 The geophysical modelling is consistent with earlier interpretations that the batholith consists of a gabbroic phase which was emplaced in the Botwood Group at 420 ± 8 Ma. A later granitic phase was emplaced at 390 ± 15 Ma. There is a close spatial relationship between the various lithologies and specific geophysical and geochemical signatures.
 
 Shaded relief techniques applied to the aeromagnetic data indicate that the batholith has undergone at least one phase of faulting. Magnetic modelling reveals inward dipping gabbro blocks along the exterior boundaries of the complex. The model derived from the limited gravity data is consistent with the magnetically modelled blocks based on more extensive data.
 
 The geophysical and geochemical data suggest the granitic portion of the batholith is smaller in volume, but larger' in area, than implied by the limited outcrop mapping. The geophysical modelling is consistent with a thin granitic phase and thicker gabbroic phase.
 
 RÉSUMÉ 
 Une étude géophysique, géologique et géochimique intégrée du complexe du mont Peyton dans le centre de Terre-Neuve à fourni des indices sur la configuration de surface et souterraine du complexe. Les données géologiques, magnétiques, gravimétriques et de cuivre, nickel et uranium nous permettent de tracer et de redéfinir les contacts lithologiques du complexe et de développer une appréciation de sa configuration possible en profondeur.
 
 La modélisation géophysique est en accord avec les interprétations antérieures selon lesquctles le batholite comprendrait une phase gabbroique qui s'est mise en place dans le Groupe de Botwood à 420 ± 8 Ma. Une phase granitique plus tardive s'est mise en place à 390 ± 15 Ma. Il y a une association spaciale étroite entre les diverses lithologies et des signatures géophysiques et géochimiques spécifique.
 
 Les techniques de relief ombragé appliquées aux données aéromagnétiques indiquent que le batholite à connu au moins une génération de failles. La modélisation des données magnétiques montre des blocs de gabbro inclinés vers l'intévieur, autour des bordures externes du complexe. Le modèle dérivé de la quantité restreinte de données gravimétriques est en accord avec les blocs de la modélisation magnéique, laquelle est basée sur une plus grande quantité de données.
 
 Les données géophysiques et géochimiques suggèrent que la partie granitique du batholite à un volume plus petit, mais une surface plus grande, que ne l’indiquent les données restreintes de cartographie de surface. La modélisation geéophysique est en accord avec une phase granitique mince et une phase gabbroique plus épaisse.
 
 [Traduit par le journal]

A new Lower Ordovician (Arenig) faunule from the Coy Pond Complex, central Newfoundland, and a refined understanding of the closure of the Iapetus Ocean

A newly discovered fossiliferous horizon within sediments belonging to the Coy Pond Complex of the Exploits Subzone in central Newfoundland yields the graptolite Undulograptus austrodentatus s.l. and cyclopygid trilobite Cyclopyge grandis brevirhachis. This late Arenig faunule constrains the upper age limit of the ophiolite complex and is the first record of an Early Ordovician cyclopygid trilobite in North America. This is consistent with a paleogeographic affinity for south-central Newfoundland with the northern oceanic margin of Avalonia in a peri-Gondwanan position during the Early Ordovician and contrasts with coeval shelly and graptolitic faunas from the Notre Dame Subzone of central Newfoundland, which show marked Laurentian affinities. The Exploits Subzone is generally considered equivalent to the region of Scotland lying south of the Southern Upland Fault. The Newfoundland discovery, which is supported by faunal data from elsewhere in Newfoundland and in Ireland, suggests that the region around the Southern Upland Fault, rather than the Solway Firth, represents the location of the "Iapetus suture" in Britain in Lower Ordovician rocks.

Geological interpretation of a high resolution reflection seismic survey at the Buchans mine, Newfoundland

Sixteen kilometres of high resolution Vibroseis reflection seismic data have been acquired in the vicinity of the former Buchans mine. Direct identification of the cause of several reflectors is possible because the geology is tightly constrained by underground workings and drill holes both of which locally exceed 1 km depth. Many of the mine-scale thrust faults are imaged as reflectors but conformable and intrusive contacts generally responded poorly. A significant shallow-dipping thrust, the Powerline Fault, is recognized below the orebodies and traced throughout the Buchans area, primarily as a result of the seismic survey. It truncates ore stratigraphy and forms the floor thrust of a large duplex–stack, which hosts all the orebodies. Its presence has negative implications for exploration in the immediate mine area. Several lines of evidence suggest that this fault has a significant component of out-of-sequence movement. A strong reflector 4.5 km below Buchans is correlated with the surface expression of the Victoria River Delta Fault, an important regional structure, newly recognized southeast of Red Indian Lake. This shallow, north-dipping sole thrust forms the structural base of the Buchans Group and brings it above a younger fossiliferous Llanvirn volcanic sequence. This fault is not itself the Red Indian Line but is one of a series of faults that collectively effect substantial geological contrasts in central Newfoundland. The seismic survey was a cost-efficient means of gaining knowledge of Buchans structure, which might otherwise have been acquired at much higher cost and over a longer period of time.

Early Silurian paleolatitude for central Newfoundland from paleomagnetism of the Wigwam Formation

Redbeds and minor volcanic rocks of the Early Silurian Wigwam Formation of the Botwood Group were sampled in the Exploits Subzone of the Dunnage Zone of central Newfoundland. At 18 sedimentary and 3 volcanic sites thermal demagnetization isolated a shallow northward (or southward) magnetization (D = 356.0°, I = −16.8°; k = 12.9; α95 = 9.2°; n = 21 site means) after correction for the tilt of bedding. A positive fold test demonstrates that this remanence predates regional Siluro–Devonian folding. A primary age for the remanence is indicated by positive conglomerate tests on volcanic clasts, and reversals correlated with sedimentary stratigraphy. Antiparallel remanence directions at sites of opposite polarity indicate that the primary remanence is not partially overprinted by a secondary component. The Exploits Subzone of the Dunnage Zone is interpreted to have been at low paleolatitudes (8.5°S ± 5°) during the Early Silurian. We reached a similar conclusion for the Notre Dame Subzone of the Dunnage Zone in a previous paleomagnetic study of Early Silurian redbeds and volcanic rocks of the King George IV Lake area. The low paleolatitudes obtained for the Wigwam and King George IV Lake rocks do not differ significantly and, hence, provide no evidence for a large ocean between the two subzones in the Early Silurian. However, the azimuthal orientation of the subzones at that time is still uncertain, and an ocean with its axis oriented in a north–south direction would not be detected by the paleomagnetic method.

Lower Ordovician (Arenig–Llanvirn) graptolites from the Notre Dame Subzone, central Newfoundland

Many lower Paleozoic rocks in the Notre Dame Subzone of central Newfoundland are of unknown or imprecise age. Several new Lower Ordovician graptolite occurrences are here reported and earlier records revised. New graptolite localities in the Balsam Bud Cove Formation at Snooks Arm on the Baie Verte Peninsula, previously recorded as "early Ordovician (Arenig)" have yielded an assemblage identical to that found in the middle part of Bed 11 of the Cow Head Group, western Newfoundland, indicating a probable lower Didymograptus bifidus Zone age. At Corner Pond, southeast of Corner Brook, an abundant, diverse fauna from the Corner Pond formation indicates a marginally older age for the black shales than those at Snooks Arm (Pendeograptus fruticosus Zone, equivalent to lower Bed 11). Black shales associated with felsic volcanics and limestone breccia belonging to the Cutwell Group at Lushes Bight, on Long Island, western Notre Dame Bay, which were previously assigned to the widespread black shales of the Lawrence Harbour Formation and equivalents in the Exploits Subzone, contain a rich lower Llanvirn (Paraglossograptus tentaculatus Zone) graptolite assemblage. This agrees with ages established using other macrofossils and conodonts from the associated limestones. In contrast, a lower shale unit from older strata at Southern Head on the eastern end of the island yields a late Arenig Isograptus victoriae maximus Zone assemblage. These newly discovered graptolite faunas provide precise ages for the upper and lower parts of the volcano-sedimentary sequence on Long Island. Interestingly, all four graptolite assemblages discussed here are of open-ocean affinity, permitting accurate correlation with localities not only in western Newfoundland but also elsewhere in the world.

Dunnage-Gander relationships and Ordovician orogeny in central Newfoundland; a sediment provenance and U/Pb age study

Dunnage-Gander relationships and Ordovician orogeny in central Newfoundland; a sediment provenance and U/Pb age study

Intra-Iapetus brachiopods from the Ordovician of eastern Ireland: implications for Caledonide correlation: Discussion

In an important paper dealing with the Hilltown brachiopod fauna of eastern Ireland and its implication for Caledonide correlation, the authors reiterate the view that the Iapetus suture of Ireland correlates with the junction between the Dunnage and Gander terranes of Newfoundland, implying thereby that the Dunnage Terrane forms part of the Laurentian oceanic margin. As a consequence they are led to propose that the rocks containing the Indian Bay fauna of the Gander Terrane (Wonderley and Neuman 1984) lie either within a klippe thrust across the suture zone or within a zone gradational with the rocks of the Gander Group. Furthermore, in allowing that the Bellewstown Terrane has affinities with part of the Dunnage, it would seem necessary that in Ireland the Early Ordovician suture be placed between the Bellewstown and Leinster terranes. It is the purpose of this discussion to suggest that the junction of the Dunnage and Gander terranes (the Reach Fault boundary of McKerrow and Cocks (1976, 1977, 1986), McKerrow (1988), and Stillman (1988)), does not represent the Iapetus suture in Newfoundland. It is argued that the faunal evidence allows location of the Iapetus cryptic suture to the north of the Exploits volcanic zone, along a Lukes Arm Red Indian line (cf. Williams et al. 1988). It is further suggested that the Exploits and Grangegeeth terranes of Newfoundland and Ireland, respectively, were located in a more oceanward position within the Avalonian margin than was the Bellewstown Terrane, from which they were separated perhaps by a backarc basin. Consequently, the Indian Bay rocks, even if thrust, need not be exotic, nor is it necessary to locate the Iapetus suture to the southeast of the Bellewstown Terrane. The assumption that the Dunnage rocks formed to the north of the Iapetus suture (e.g., Arnott et al. 1985; Stillman 1988) is largely based on the conclusions of McKerrow and Cocks (1977) concerning the paleogeographic significance of the shelly faunas of central Newfoundland. Counter to earlier interpretations placing Iapetus along a Solway Lukes Arm line (Church and Gayer 1973), McKerrow and Cocks (1977) located the Iapetus suture along the Reach Fault on the basis of their identification of a Caradocian fauna in the Cobbs Arm Limestone of New World Island. The Early Ordovician faunas of New World Island that were obviously not Scoto-Appalachian were explained as having developed endemically (McKerrow and Cocks 1977, p. 493). However, the Early Ordovician faunas of New World Island and Anglesey were subsequently shown by Neuman and Bates (1978) to belong to a common Celtic biogeographic province. Further-

The seismic velocity structure of northern Appalachian crust around western Newfoundland

The crustal velocity structure beneath western Newfoundland is constrained by a reanalysis of older, regional refraction profiles together with an analysis of one new profile. Initial interpretation of the older data gave inconsistent and discontinuous structures that are difficult to reconcile with more recent deep reflection profiles. We also show that traveltimes predicted by the earlier models often do not yield acceptable fits to the original observations. Our reinterpretation reveals a simpler pattern, in which the crust is characterized by a persistent, high-velocity, lower crustal (HVLC) layer. This layer has velocities of 7.0–7.9 kmls and thicknesses of 5–23 km. It is thickest beneath the Grenville crustal block, east of the Appalachian structural front, and thins or is possibly absent within the Central block. Analysis of the new, much higher resolution profile off western Newfoundland confirms the existence of the HVLC layer with a velocity of 7.2 kmls and thicknesses of 11–19 km, increasing to the northeast. The upper crust has well-defined velocities of 6.2–6.4 kmls and is overlain by a complex sandwich of sediment layers with principal velocities of 3.9, 4.95, and 5.58 kmls and maximum total thicknesses of 8.5 km in the south to 5.5 km in the north. Total crustal thickness varies from 39 to 43 km from south to north. Comparison of the velocity–depth models with the pattern of deep crustal reflectivity revealed by deep multichannel profiles shows that the HVLC layer is coincident with a zone of flat-lying reflectors that terminate to the west at the base of the crust beneath the Appalachian structural front. The HVLC may continue eastward to cover a broad region of central Newfoundland as suggested by the older data, but its association with the reflectivity is not clear.

Influence of moose browsing on successional forest growth on black spruce sites in Newfoundland

Two 225 m 2 exclosures established in 1976 to eliminate browsing by moose ( Alces alces Gray), were examined for tree growth and density, and species composition in 1987. Density of balsam fir ( Abies balsamea L.), pin cherry ( Prunus pensylvanica L. fil), and high-bush cranberry ( Viburnum trilobum Marsh.) were higher inside the exclosures than outside. In the case of balsam fir, there was a significantly greater number of short (< m) dead and moribund stems outside both exclosures which had suffered browsing for 15 years. Balsam fir inside the exclosures that had been browsed were recovered. Heights of balsam fir inside were significantly higher than outside exclosures (1.01 m vs 0.60 m) and mean annual growth rate was more than three times greater inside. White birch ( Betula papyrifera Marsh.) were significantly taller inside both exclosures compared with outside although densities were similar. Most black spruce ( Picea mariana Mill.) had attained a mean height of more than 3 m, with a density of about 1800 stems/ha. Browsing has resulted in an open stand dominated by tall black spruce with small (< 1 m) balsam fir as an understorey. The expected regeneration pattern for this site is predominantly to balsam fir. We conclude that moose are altering forest successional patterns on black spruce sites in central Newfoundland.

Paleogeography of some vestiges of Iapetus: Paleomagnetism of the Ordovician Robert's Arm, Summerford, and Chanceport Groups, central Newfoundland

In the Central Mobile Belt of Newfoundland, three volcanic groups of early Middle Ordovician age (Robert9s Arm, Summerford, and Chanceport) are thought to have formed within the Iapetus Ocean. Demagnetization analyses of 328 samples from these three groups has yielded similar magnetic directions, calculated by combining stable end-point directions and great-circle poles. The three groups yield similar poles located at 6°N, 140°E; 8°N, 140°E; and 10°N, 131°E, corresponding to paleolatitudes of about 30°S. The magnetization of the Robert9s Arm Group passes the tilt test, and one site shows normal polarity, antipodal to the directions of the other sites. The paleolatitude of 31°S places the volcanic rocks at the time of their formation in the middle of Iapetus, between the Laurentian margin at about 15°S and the location of the Avalon Terrane at >50°S. Subsequent accretion to Laurentia and the presently adjacent island-arc rocks represented by the Moreton9s Harbour Group occurred after northward drift in the later Ordovician/earliest Silurian and before the Middle Silurian.

Secondary school students' understanding of the nature of science

A stratified random sample of 32 secondary students chosen from nine schools in eastern and central Newfoundland, Canada, were interviewed to determine their views of the nature of science. The interview transcripts were reduced to a set of individualized conceptual inventories. A number of general trends were identified. Most students were found to have difficulty establishing the domain of science, although many tended to view the practice of science as cumulative. Although the majority of the sample asserted that scientific information was tentative and provisional, they tended to regard factual information in science to be absolute and irrefutable. Scientific theories appeared to be understood only in a naive sense in that most students regarded theories as suggested explanations for fairly discrete events as opposed to elaborate interpretive frameworks. In accordance with previously documented evidence (Aikenhead, Fleming & Ryan, 1987) many students were found to equate the term “scientific law” with the more common legal usage of the word. Finally, elements of what Nadeau and Desautels (1984) term as naive realism, blissful empiricism, credulous experimentalism and excessive rationalism were quite prevalent.

Test of airborne, side-looking synthetic-aperture radar in central Newfoundland for geological reconnaissance : Can J Earth Sci V28, N2, Feb 1991, P257–265

Test of airborne, side-looking synthetic-aperture radar in central Newfoundland for geological reconnaissance : Can J Earth Sci V28, N2, Feb 1991, P257–265

Silurian (Llandovery) graptolites from the Bay of Exploits, north-central Newfoundland, and their geological significance

Only one specimen of a Silurian graptolite has ever been recorded from Newfoundland, and it was not identifiable below generic level. The graptolite assemblage discussed and figured here, from a sequence of turbidites on Upper Black Island, north-central Newfoundland, includes the first positively identified Silurian taxa from the province, and provides the first unequivocal evidence of Silurian oceanic sedimentation in the Dunnage Zone. The graptolite taxa include Rastrites peregrinus (Barrande), Coronograptus? sp. cf. C. gregarius (Lapworth), Monograptus austerus sequens Hutt?, Orthograptus insectiformis (Nicholson), Monograptus spp. indet., "Climacograptus"? sp., and Glyptograptus? sp. This assemblage demonstrates that the strata, previously assigned to the Middle Ordovician Lawrence Harbour Formation, are actually Aeronian (middle Llandovery) in age and that the turbidites considerably postdate both the Lawrence Harbour and Point Leamington formations of the Exploits Subzone. Furthermore, the graptolite fauna is similar to that found in coeval sediments in the United Kingdom and Scandinavia but unlike any assemblages known from elsewhere in North America. This suggests the presence of open oceanic conditions, or deep marginal basins during the Llandovery hosting graptolites with European affinities, and raises the possibility that at least part of the Iapetus Ocean was still open in central Newfoundland during Early Silurian times.