The 35.5 m thick Anisian section of theWinterswijkse Steen- en Kalkgroeve (Eastern Netherlands) comprises the Upper Röt (Upper Röt Claystone Member) to the basal Lower Muschelkalk (Oolith Member). In the section 15 terrestrial or marine influenced parasequences are recognized. A fourth order sequence shows the increasing marine influence. New marker beds, ten vertebrate track beds, three bone beds and cephalopod remains have been documented. This enabled correlation to other sections in NW Germany. The tracks found in the Winterswijkse Steen- en Kalkgroeve at the boundary Röt/Lower Muschelkalk are linked to the oldest known vertebrate skeleton remains of the Germanic Basin. It is the first time that the exact stratigraphic position of these vertebrate remains has been established. In the terrestrial influenced section of the Winterswijkse Steen- en Kalkgroeve, the well preserved vertebrate track ways and vertebrate fauna will be of international importance and will provide new data of theTriassic carbonate tidal flat megatracksite concept and reptiles living in this environment.

In the Netherlands, over 190 gas fields of varying size have been exploited, and 15% of these have shown seismicity. The prime cause for seismicity due to gas depletion is stress changes caused by pressure depletion and by differential compaction. The observed onset of induced seismicity due to gas depletion in the Netherlands occurs after a considerable pressure drop in the gas fields. Geomechanical studies show that both the delay in the onset of induced seismicity and the nonlinear increase in seismic moment observed for the induced seismicity in the Groningen field can be explained by a model of pressure depletion, if the faults causing the induced seismicity are not critically stressed at the onset of depletion. Our model shows concave patterns of log moment with time for individual faults. This suggests that the growth of future seismicity could well be more limited than would be inferred from extrapolation of the observed trend between production or compaction and seismicity. The geomechanical models predict that seismic moment increase should slow down significantly immediately after a production decrease, independently of the decay rate of the compaction model. These findings are in agreement with the observed reduced seismicity rates in the central area of the Groningen field immediately after production decrease on 17 January 2014. The geomechanical model findings therefore support scope for mitigating induced seismicity by adjusting rates of production and associated pressure change. These simplified models cannot serve as comprehensive models for predicting induced seismicity in any particular field. To this end, a more detailed field-specific study, taking into account the full complexity of reservoir geometry, depletion history and mechanical properties, is required.

Geothermal low enthalpy heat in non-magmatic areas can be produced by pumping hot water from aquifers at large depth (>1 km). Key parameters for aquifer performance are temperature, depth, thickness and permeability. Geothermal exploration in the Netherlands can benefit considerably from the wealth of oil and gas data; in many cases hydrocarbon reservoirs form the lateral equivalent of geothermal aquifers. In the past decades subsurface oil and gas data have been used to develop 3D models of the subsurface structure. These models have been used as a starting point for the mapping of geothermal reservoir geometries and its properties. A workflow was developed to map aquifer properties on a regional scale. Transmissivity maps and underlying uncertainty have been obtained for 20 geothermal aquifers. Of particular importance is to take into account corrections for maximum burial depth and the assessment of uncertainties. The mapping of transmissivity and temperature shows favorable aquifer conditions in the northern part of the Netherlands (Rotliegend aquifers), while in the western and southern parts of the Netherlands aquifers of the Triassic and Upper Cretaceous / Jurassic have high prospectivity. Despite the high transmissivity of the Cenozoic aquifers, the limited depth and temperature reduce the prospective geothermal area significantly.

The results show a considerable remaining uncertainty of transmissivity values, due to lack of data and heterogeneous spatial data distribution. In part these uncertainties may be significantly reduced by adding well test results and facies parameters for the map interpolation in future work. For underexplored areas this bears a significant risk, but it can also result in much higher flowrates than originally expected, representing an upside in project performance.

A selection of reflection-seismic lines from the southern part of the Central European Basin System and its southern margin were used to establish the spectrum of extensional and compressional deformation structures and to calibrate the timing of these events. The lines are arranged in a N-S and an E-W transect running across the Pompeckj Block and the Lower Saxony Basin in Northern Germany. The structural record provided by the seismic data points to an interplay between far-field horizontal stresses and vertical movements of the basin floor, the latter only weakly correlated with the development of seismic-scale tectonic structures. A detailed seismo-stratigraphic analysis indicates that Late Triassic-Jurassic extension has been the principal control on the structure of the E-W profile, whereas the N-S profile is dominated by compressional structures associated with Late Cretaceous inversion. Overprint effects of extension and inversion tectonics can be classified among a few distinct tectonic events accompanied by movements of the Upper Permian salt: firstly, an episode of subsidence and diapiric rise in the Keuper; secondly, a clear Jurassic-to-Early Cretaceous extension recorded by normal faulting and differential subsidence. The latter was interrupted by a major episode of Late Jurassic uplift. Thirdly, a Late Cretaceous-Early Paleogene basin inversion was associated with approximately N-S compression; and fourthly, recurring extension during the Cenozoic associated with diapiric rise and collapse. The Mesozoic extension is expressed in a number of normal faults that were most active during the Early Cretaceous localised subsidence within the Lower Saxony Basin. The deformation associated with the Late Cretaceous inversion was partly decoupled along the salt. The compressional deformation at the southern margin of the basin was thick-skinned in style, characterized by folding and faulting of the Mesozoic sedimentary fill and pre-Zechstein strata. Further north, towards the centre of the basin, folding and reverse faulting were mostly concentrated above the salt. The tectonic evolution of the investigated area suggests the presence of a zone of crustal weakness along the SW margin of the Central European Basin System which allowed strain localization in response to a favourable oriented stress field.

The Netherlands has ample geothermal resources. During the last decade, development of these resources has picked up fast. In 2007 one geothermal system had been realised; to date (1 January 2019), 24 have been. Total geothermal heat production in 2018 was 3.7 PJ from 18 geothermal systems. The geothermal sources are located in the same reservoirs/aquifers in which the oil and gas accumulations are hosted: Cenozoic, Upper Jurassic – Lower Cretaceous, Triassic and Rotliegend reservoirs. Additionally, the yet unproven hydrocarbon play in the Lower Carboniferous (Dinantian) Limestones delivered geothermal heat in two geothermal systems. This is in contrast to the Upper Cretaceous and Upper Carboniferous with no producing geothermal systems but producing hydrocarbon fields. Similar to hydrocarbon development, developing the geothermal source relies on fluid flow through the reservoir. For geothermal application a transmissivity of 10 Dm is presently thought to be a minimum value for a standard doublet system. Regional mapping of the geothermal plays, with subsequent resource mapping, by TNO discloses the areas with favourable transmissivity within play areas for geothermal development. The website www.ThermoGis.nl provides the tool to evaluate the geothermal plays on a sub-regional scale. The Dutch geothermal source and resource portfolio can be classified using geothermal play classification of, for example, Moeck (2014). An appropriate adjective for play classification for the Dutch situation would be the predominant permeability type: matrix, karst, fracture or fault permeability. The Dutch geothermal play is a matrix-permeability dominated ‘Hot Sedimentary Aquifer’, ‘Hydrothermal’ or ‘Intra-cratonic Conductive’ play. The Dutch ‘Hot Sedimentary Aquifer’ play is subdivided according to the lithostratigraphical annotation of the reservoir. The main geothermal plays are the Delft Sandstone and Slochteren Sandstone plays.

Application of the traditional lithostratigraphic framework to subdivide theMiddle- and Upper-Quaternary locally-derived fine-grained deposits in theNetherlands is problematic. Deposits of many formations cannot bedistinguished from each other based on lithological characteristics andstratigraphie position alone. To overcome this problem, we present a new,well-defined lithostratigraphy for these deposits, based on detailedresearch in the central part of the Roer Valley Graben. This area containsan up to 35 m-thick sedimentary record of Middle- and Upper-Quaternary sand,loam and peat deposits. These have mainly been formed by aeolian andsmall-scale fluvial processes and have been preserved as a result oftectonic subsidence. The traditional lithostratigraphic subdivision of thesedeposits into three formations (Eindhoven Formation, Asten Formation andTwente Formation) was based on a combination of litho-, bio- andchronostratigraphic evidence and the presumed widespread presence of ahorizon of organic-rich interglacial sediments of Eemian age. To avoidintermingling of criteria regarding lithological characteristics, genesisand age, we now incorporate all fine-grained sediments into the new BoxtelFormation. The implications for the lithostratigraphic framework in otherparts of the country are explored and discussed. Eight lithostratigraphicmembers are introduced that describe the most characteristic parts of theformation. To fully illustrate the sedimentary sequence in the Roer ValleyGraben, two new members are defined here. The Best Member incorporatesalternating floodloam deposits and sandy aeolian deposits in the lower partof the Boxtel Formation. The Liempde Member includes reworked aeolian loessand sandy loess deposits (‘Brabant loam’) that occur in the upper part ofthe sedimentary sequence.

At the locality of Heidebos (Moervaart area, N Flanders, Belgium), a sedimentary core was taken in the Maldegem-Stekene coversand ridge and dated using optically stimulated luminescence (OSL). The study aimed at contributing to an improved understanding of the evolution of the physical landscape around archaeological settlements in this area. The core comprised a 7 m thick series of laminated and massive aeolian sands, in which several organic layers were intercalated. From this sequence, 11 samples were collected for quartz-based SAR-OSL dating; an internally consistent dataset was obtained. The ages of the lowermost 1 m of the sedimentary sequence (15.5±1.1 ka and 17.3±1.3 ka) imply that these sediments may represent the time-equivalent deposit of a deflation phase that occurred during the Late Pleniglacial and led to the formation of a widespread desert pavement, regionally known as the Beuningen Gravel Bed. However, a significant part of the sediments (at least 4 m) was deposited later, i.e. during the Allerød and/or the Late Dryas. As such, the results allow establishing the genesis of the coversand ridge at the Heidebos locality on the basis of direct age information. The relatively high sedimentation rate and the absence of extensive soil formation in the record reflect periods of pronounced aeolian activity and landscape instability during the Late Glacial, which provides part of the environmental framework for human occupation in the area.

The Gelderse IJssel is the third major distributary of the Rhine in the Netherlands and diverts on average ~15% of the Rhine discharge northward. Historic trading cities are located on the Gelderse IJssel and flourished in the late Middle Ages. Little is known about this river in the early Middle Ages and before, and there is considerable debate on the age and origin of the Gelderse IJssel as a Rhine distributary. A small river draining the surrounding Pleistocene uplands must have been present in the IJssel valley during most of the Holocene, but very diverse opinions exist as to when this local river became connected to the Rhine system (and thereby to a vast hinterland), and whether this was human induced or a natural process. We collected new AMS radiocarbon evidence on the timing of beginning overbank sedimentation along the lower reach of the Gelderse IJssel. Our data indicate onset of overbank sedimentation at about 950 AD in this reach. We attribute this environmental change to the establishment of a connection between the precursor of the IJssel and the Rhine system by avulsion. Analysis of previous conventional radiocarbon dates from the upper IJssel floodplain yields that this avulsion may have started ~600 AD. Our results contradict earlier suppositions, based on interpretation of archaeological data and historical accounts, that the Gelderse IJssel is much older and originated as a canal, dug under supervision of the Roman general Drusus.

The classical problem of the nature and age of the Rupelian-Chattian (Early-Late Oligocene) unconformity in its type region is here approached using organic walled dinoflagellate cyst (dinocyst) correlations between the North Sea Basin and well-calibrated central Italian (Tethyan Ocean) sections. Useful Oligocene dinocyst events are the last occurrence of Enneadocysta pectiniformis (~29.3 Ma), and the first occurrences of Saturnodinium pansum (~29.4 Ma), Distatodinium biffii (~27.9 Ma) and Artemisiocysta cladodichotoma (~26.7 Ma).The latter event marks the earliest Chattian. The improved correlations indicate that the Rupelian-Chattian (R-C) boundary is associated with the so-called ‘Oligocene Glacial Maximum’. This phase of important global cooling and glacio-eustatic sea level fall is genetically related to the unconformity between the classic Oligocene stages. Subsequent global warming (so-called ‘Late Oligocene Warming Event’), induced a major sea level rise, leading e.g. to the time-transgressive deposition of the typical basal Chattian glauconitic sands. The oldest of the Chattian units have a GPTS age of-26.7 Ma. It further appears that a hiatus of ~500 kyrs spans the classic Rupelian-Chattian unconformity.

Tidal channel networks, estuaries and ebb deltas are usually formed over a period longer than observations cover. Much is known about their characteristics and formation from linear stability analyses, numerical modelling and field observations. However, experiments are rare whilst these can provide data-rich descriptions of morphological evolution in fully controlled boundary and initial conditions. Our objective is to ascertain whether tidal basins can be formed in experiments, what the possible scale effects are, and whether morphological equilibrium of such systems exists.

We experimentally created tidal basins with simple channel networks and ebb deltas in a 1.2 by 1.2 m square basin with either a fixed or self-formed tidal inlet and initially flat sediment bed in the tidal basin raised above the bed of the sea. Rather than create tides by varying water level, we tilted the entire basin over the diagonal. The advantage of this novel method is that the bed surface slopes in downstream direction both during flood and ebb phases, resulting in significant transport and morphological change in the flood phase as well as the ebb phase. This overcomes the major problem of earlier experiments which were entirely ebb-dominated, and reduces the experiment time by an order of magnitude.

Ebb deltas formed in sand were entirely bedload dominated whereas the lightweight plastic sediment was intermittently suspended. Channels bifurcated during channel deepening and backward erosion to form a network of up to four orders. For initially dry tidal plains, the tidal prism increased as more sediment eroded from basin to ebb delta, so that evolution accelerated initially. The rate of change, the size of the channels and the final length of channels and delta were very sensitive to the tidal amplitude, tidal period and initial water depth in the basin. Most experiments with sand terminated with all sediment below the threshold for motion, whilst lightweight sediment remained mobile in the inlet region and firstorder channels, suggesting that sustained morphodynamics are feasible in experiments. We discuss how this novel experimental setup can be extended to produce tidal deltas, estuaries and other tidal systems and study their dynamics as a function of their forcing.

The histology of a femur of Plagiosuchus, a Middle Triassic temnospondyl amphibian, is described on the basis of two supplementary methods: classic thin sectioning and micro-CT scanning. In addition, the effectiveness of high-resolution micro-CT scanning for histological analysis is assessed. A classic, mid-shaft thin section of the femur was prepared, but prior to slicing two micro-CT scans were made. One of these has an image stack of a total of 1,024 images in the horizontal plane and a slice thickness of 87.8 μm, so that the entire bone could be captured, while the second was at mid-shaft region only, yet with a higher resolution of 28.3 μm and an image stack of 787 images in the horizontal plane. The classic thin section shows a very small medullary region which is surrounded by a layer of endosteal bone. The thick cortex is highly porous with numerous large, mainly longitudinal, vascular canals arranged in layers. In the deepest cortex woven bone occurs and primary osteons had locally started to form (incipient fibro-lamellar bone), which gradually passes into parallel-fibred bone and more lamellar bone close to the outer surface. Remains of a Kastschenko line were identified, enabling a reconstruction of the entire growth record. Five Lines of Arrested Growth (LAG) could be counted. The micro-CT scan enabled observations of the ontogenetic growth stages and calculation of growth rate on the basis of a single specimen. The micro-CT scan permitted a reconstruction of the ontogenetic development and the exact deposition rate per annum. Moreover, at higher resolution the micro-CT scan revealed data on micro-anatomical characters, such as porosity and skeletochronology (growth mark count). In conclusion, micro-CT scans do provide an alternative in cases where thin sectioning of the original bone is not possible.

The relevance of a study of the Eemian occupation of Europe lies largely in the discussion on the environmental tolerances of early humans and in the limits encountered during the reconstruction of Palaeolithic habitats. The traditional vision is reviewed; then follows a discussion of Gamble’s studies (1986, 1987) in which he postulated an absence of human occupation in North-Western Europe during the Eemian. Gamble’s explanatory models and the reactions to his work are presented. Finally, the relation is considered between the distribution pattern of sites, the former dispersal of early humans across the European landscape, and the implications of this evidence for hypotheses of environmental tolerances of Palaeolithic humans.

This paper presents and discusses the distribution of fluid and leak-off pressure data from the subsurface of onshore and offshore Netherlands in relation to causes of formation fluid overpressure and the permeability framework. The observed fluid pressure conditions demonstrate a clear regional difference between the southern and the north and north-eastern part of the study area. In the southern area, formation fluid pressures are close to normal and well below measured leak-off pressures. In the north, formation fluids are overpressured and may locally even approach the measured leak-off pressures. The regional differences in fluid overpressure can, in large part, be explained by differences in geologic framework and burial history. In the south, relatively low rates of sedimentary loading and the presence of relatively permeable sedimentary units have led to the currently observed normally pressured conditions. In the northern area, relatively rapid Neogene sediment loading plays an important role in explaining the observed overpressure distributions in Cenozoic mudstones, Cretaceous Chalk and Rijnland groups, and probably also in Jurassic units. The permeability framework of the northern and north-eastern area is significantly affected by Zechstein and Triassic salt deposits and structures. These units are characterised by very low permeability and severely restrict fluid flow and pressure dissipation. This has created hydraulically restricted compartments with high overpressures (for example overpressures exceeding 30 MPa in the Lower Germanic Trias Group in the Terschelling Basin and Dutch Central Graben).

In July 2007 an important archaeological find was made in the Op de Schans loess pit near Kesselt (Belgian Limburg) immediately to the west of the Dutch city of Maastricht. During an archaeological rescue dig, three Lower Palaeolithic artefacts were recovered from the infill of an ancient erosion gully: a bifacial side-scraper, an atypical biface and a cortical flake. Typologically, the artefacts can be classified as Acheulean. In this region, harbouring several such brickyard pits, these are the oldest artefacts yet found, prompting further investigations into the stratigraphic position of the archaeological layer. The Op de Schans pit, which has yielded several Middle Palaeolithic occupation horizons, is located in the middle of an ancient sediment trap. Because of this exceptional geomorphologic situation, multiple ancient sediments have been preserved which elsewhere were entirely removed during subsequent erosion phases. Here five separate loess beds with intercalated interglacial palaeosols are present, overlying the deposits of the River Maas (Meuse). This sequence has been used as a hypothetical framework for elaborating a chronostratigraphic model. The archaeological level in question, discovered at the base of a subsequently infilled erosion gully, can most likely be chronostratigraphically dated to around the start of Marine Isotope Stage 10 (MIS 10), in the era of the Pottenberg discordance (approx. 390 ka). However, the possibility cannot be excluded that the gully in which the artefacts were found dates from an early phase of MIS 12 (approx. 480 ka). The age may in fact be greater still, as the artefacts have been eroded out of their original, primary context and subsequently deposited in the gully. Hypothetically, they may even have been taken up from the Maas loam of the Kesselt Maas terrace (MIS 13) that here is situated directly below the archaeological horizon. This would make the maximum age of the artefacts recovered from the gully around 500 ka.

In order to validate existing models of sedimentation in active sedimentary environments, detailed stratigraphic information is indispensable. Near-surface geophysical methods provide a means to acquire high-resolution images of the stratigraphic succession in the shallow subsurface. Land-based and marine methods have been tested in the Verdronken Land van Saeftinge. This intertidal flat area is cut by numerous tidal gullies, and high tidal amplitudes enable the application of different techniques at various water levels. Data acquisition focused on the upper 10 – 20 m of the active sediment bodies. Applied techniques include high-resolution seismic acquisition, geo-electrical methods (DC resistivity), electromagnetic techniques, CPT, and manual drilling. In general the acoustic methods allowed more reliable and detailed interpretation of the sedimentary structures than the electric/electromagnetic methods. The latter suffered from the effect of tidal action and salt-water intrusion, and their application on land proved very strenuous. CPT and shallow cores provided valuable ground-truth information. The results clearly indicate that no single technique can provide all the answers. Only an integrated use of (complementary) methods will allow getting a better grip on the sedimentary architecture and preservation potential in active estuarine sedimentary environments.

As part of the activities of the Collaborative Research Centre ‘SFB 350’, measurements of geodetic and geodynamic changes in the area of the Lower Rhine Embayment and the Rhenish Shield are being performed at different scales in space and time. Continuous borehole tilt measurements and repeated microgravimetric surveys yield information on the local stability of the ground and changes in horizontal gravity gradients that are both dominated by seasonal fluctuations. Results of more than seven years of regular GPS campaigns are discussed in terms of vertical and horizontal point motions. The most prominent motions are man-induced effects occurring in or near the browncoal mining areas, where groundwater withdrawal produces subsidence of up to 2.2 cm/y in the area under investigation. Horizontal and vertical motions at other GPS points are smaller by one order of magnitude and in most cases are only marginally detectable. The eastward motion of two points in the Bergisches Land and the westward motion of two points in the Eifel near the Belgian border may be interpreted as a result of the ongoing extension of the Cenozoic rift system in the western part of the Eurasian plate.

The shallow subsurface of Groningen, the Netherlands, is heterogeneous due to its formation in a Holocene tidal coastal setting on a periglacially and glacially inherited landscape with strong lateral variation in subsurface architecture. Soft sediments with low, small-strain shear wave velocities (VS30 around 200 m s−1) are known to amplify earthquake motions. Knowledge of the architecture and properties of the subsurface and the combined effect on the propagation of earthquake waves is imperative for the prediction of geohazards of ground shaking and liquefaction at the surface. In order to provide information for the seismic hazard and risk analysis, two geological models were constructed. The first is the ‘Geological model for Site response in Groningen’ (GSG model) and is based on the detailed 3D GeoTOP voxel model containing lithostratigraphy and lithoclass attributes. The GeoTOP model was combined with information from boreholes, cone penetration tests, regional digital geological and geohydrological models to cover the full range from the surface down to the base of the North Sea Supergroup (base Paleogene) at ~800 m depth. The GSG model consists of a microzonation based on geology and a stack of soil stratigraphy for each of the 140,000 grid cells (100 m × 100 m) to which properties (VS and parameters relevant for nonlinear soil behaviour) were assigned. The GSG model serves as input to the site response calculations that feed into the Ground Motion Model. The second model is the ‘Geological model for Liquefaction sensitivity in Groningen’ (GLG). Generally, loosely packed sands might be susceptible to liquefaction upon earthquake shaking. In order to delineate zones of loosely packed sand in the first 40 m below the surface, GeoTOP was combined with relative densities inferred from a large cone penetration test database. The marine Naaldwijk and Eem Formations have the highest proportion of loosely packed sand (31% and 38%, respectively) and thus are considered to be the most vulnerable to liquefaction; other units contain 5–17% loosely packed sand. The GLG model serves as one of the inputs for further research on the liquefaction potential in Groningen, such as the development of region-specific magnitude scaling factors (MSF) and depth–stress reduction relationships (rd).

The vegetational and climatic developments during the Riss-Würm interglacial in the area on the northern flank of the Alps are reviewed. Reforestation seems to have begun over the whole region with a dwarf-shrub and ensuing shrub phase, leading to birch and/or pine woodland. The rise in summer temperatures, which δ180 values suggest to have been a two-stage event, permitted the immigration and expansion of more demanding trees (elm, oak, lime, ash, ivy, hazel, yew, etc.). Following the thermal maximum, which took place during the hazel and yew biozones, hornbeam dominated the forests in the alpine foreland, whilst fir/spruce forests formed the dominant vegetation at sites closer to the Alps or at a higher altitude. A marked climatic deterioration can only be recognised towards the end of the interglacial, which led to extensive spruce/pine and, finally, almost pure pine forests.

This paper describes the Raman and infrared spectroscopy of SrSO4 or celestine from the Muschelkalk of Winterswijk, The Netherlands. The infrared absorption spectrum is characterised by the SO42-modes V1 at 991 cm-1, v3 at 1201, 1138 and 1091 cm-1, and v4 at 643 and 611 cm-1. An unidentified band is observed at 1248 cm-1. In the Raman spectrum at 293 K the V1 mode is found at 1000 cm-1 and is split in two bands at 1001 and 1003 cm-1 upon cooling to 77 K.The v2 mode, not observed in the infrared spectrum, is observed as a doublet at 460 and 453 cm-1. The v3 mode is represented by four bands in the Raman spectrum at 1187, 1158, 1110 and 1093 cm-1 and the v4 mode as three bands at 656, 638 and 620 cm-1. Cooling to 77 K results in a general decrease in bandwidth and a minor shift in frequencies. A decrease in intensities is observed upon cooling to 77 K due to movement of the Sr atom towards one or more of the oxygen atoms in the sulfate group.

The mosasaurine Clidastes sp. is recognised from cranial and post-cranial remains collected at four localities in NW Germany. Cranial material was found in pelagic turbiditic marls which crop out near the village of Beckum, while post-cranial skeletal elements were collected from sandy limestones exposed near the villages of Schöppingen, Coesfeld and Billerbeck. In stratigraphic order, the units producing these specimens of Clidastes are the Coesfeld, Baumberge and Beckum formations of late Campanian (Late Cretaceous) age. The cranial material comprises the anterior part of a skull and a single isolated tooth, while post-cranial bones comprise a few isolated vertebrae and a partial skeleton including forelimb bones and an articulated vertebral column. Clidastes is known to date from the western North Sea Basin (England), southern Sweden, as well as from North America (Western Interior Seaway and Gulf Coast).