Lealt Shale

Last updated

Lealt Shale Formation
Stratigraphic range: Bathonian
O
S
D
C
P
T
J
K
Pg
N
Lealt Shale Lava.jpg
Thinly bedded limestones of the Lealt Shale formation overlain by Paleogene lava
Type Geological formation
Unit of Great Estuarine Group
Sub-unitsKildonnan Member, Lonfearn Member
Underlies Valtos Sandstone Formation
Overlies Elgol Sandstone Formation
ThicknessBetween 45 and 50 m
Lithology
Primary Mudstone
Other Limestone
Location
Region Europe
CountryFlag of Scotland.svg  Scotland
Extent Inner Hebrides
Type section
Named for Lealt, Skye
Named byHarris and Hudson
LocationCliffs east of Lonfearn (partial), Coastal exposure 2.5 km north of Kildonnan, Eigg (partial)
Year defined1980
Thickness at type sectionLonfearn: 26 to 30 m (partial) Kildonnan: 23 m (partial)

The Lealt Shale Formation is a Middle Jurassic geologic formation in Scotland. Fossil ornithopod, theropod and stegosaur tracks, a theropod dinosaur tooth and the pterosaur Dearc have been reported from the formation. [1] [2] [3] The lithology consists of silty fissile mudstones with subordinate thin limestones. [4]

Contents

Fossil content

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Dinosaurs

Theropoda

Theropod of the Lealt Shale Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Theropoda Indet.IndeterminateTooth

Pterosaurs

Pterosaurs of the Lealt Shale Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Dearc [5] D. sgiathanachA angustinaripterin rhamphorhynchid
Dearc restoration.jpg

Fish

Fishes of the Lealt Shale Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Archaeotolithus [6] A. eiggensisA ray-finned fish
A. invernizziae
Leptolepis [6] L. flexuosusa leptolepid fish
L. skyensis

See also

Footnotes

  1. Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.
  2. Young, Chloe M. E.; Hendrickx, Christophe; Challands, Thomas J.; Foffa, Davide; Ross, Dugald A.; Butler, Ian B.; Brusatte, Stephen L. (May 2019). "New theropod dinosaur teeth from the Middle Jurassic of the Isle of Skye, Scotland". Scottish Journal of Geology. 55 (1): 7–19. doi:10.1144/sjg2018-020. hdl: 20.500.11820/063549bc-2a00-4ddc-bcf6-a1bc2f872c26 . ISSN   0036-9276. S2CID   134102042.
  3. dePolo, Paige E.; Brusatte, Stephen L.; Challands, Thomas J.; Foffa, Davide; Wilkinson, Mark; Clark, Neil D. L.; Hoad, Jon; Pereira, Paulo Victor Luiz Gomes da Costa; Ross, Dugald A.; Wade, Thomas J. (11 March 2020). Fiorillo, Anthony R. (ed.). "Novel track morphotypes from new tracksites indicate increased Middle Jurassic dinosaur diversity on the Isle of Skye, Scotland". PLOS ONE. 15 (3): e0229640. doi: 10.1371/journal.pone.0229640 . ISSN   1932-6203. PMC   7065758 .
  4. "Lealt Shale Formation". BGS Lexicon of Named Rock Units. Retrieved 22 February 2022.
  5. Jagielska, N.; O'Sullivan, M.; Funston, G. F.; Butler, I. B.; Challands, T. J.; Clark, N. D. L.; Fraser, N. C.; Penny, A.; Ross, D. A.; Wilkinson, M.; Brusatte, S. L. (2022). "A skeleton from the Middle Jurassic of Scotland illuminates an earlier origin of large pterosaurs". Current Biology . 32 (6): 1446–1453.e4. Bibcode:2022CBio...32E1446J. doi: 10.1016/j.cub.2022.01.073 . hdl: 10023/27028 . PMID   35196508. S2CID   247013664.
  6. 1 2 Schwarzhans, W. W.; Wakefield, M. I. (2024). "Otoliths from the Lealt Shale Formation, Great Estuarine Group, Middle Jurassic (Bathonian), Inner Hebrides, Scotland". Scottish Journal of Geology. 60 (2): 002. Bibcode:2024ScJG...60....2S. doi:10.1144/sjg2024-002.

Related Research Articles

<span class="mw-page-title-main">Trotternish</span> Northernmost peninsula of the Isle of Skye in Scotland

Trotternish is the northernmost peninsula of the Isle of Skye in Scotland, spanning in length from Portree to Rubha Hunish. The Trotternish escarpment runs almost the full length of the peninsula, some 30 kilometres, and contains landmarks such as the Old Man of Storr and the Quiraing. The summit of The Storr, overlooking the Old Man, is the highest point of the peninsula at 719 m above sea level. The north-eastern part of the peninsula around Quiraing is designated as a National Scenic Area and the entire escarpment is a Special Area of Conservation.

<span class="mw-page-title-main">Oxford Clay</span> Jurassic rock formation in southeast England

The Oxford Clay is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay Formation dates to the Jurassic, specifically, the Callovian and Oxfordian ages, and comprises two main facies. The lower facies comprises the Peterborough Member, a fossiliferous organic-rich mudstone. This facies and its rocks are commonly known as lower Oxford Clay. The upper facies comprises the middle Oxford Clay, the Stewartby Member, and the upper Oxford Clay, the Weymouth Member. The upper facies is a fossil poor assemblage of calcareous mudstones.

<span class="mw-page-title-main">Duntulm</span> Human settlement in Scotland

Duntulm is a township situated on the northwest coast of the Trotternish peninsula on the Isle of Skye, and is made up of Shulista and South Duntulm. It is located on the single-track A855 road about 24 miles north of Portree. The township is noted for its long fortified headland, which the ruins of Duntulm Castle presently sit.

<span class="mw-page-title-main">Kimmeridge Clay</span> Geological formation in England

The Kimmeridge Clay is a sedimentary deposit of fossiliferous marine clay which is of Late Jurassic to lowermost Cretaceous age and occurs in southern and eastern England and in the North Sea. This rock formation is the major source rock for North Sea oil. The fossil fauna of the Kimmeridge Clay includes turtles, crocodiles, sauropods, plesiosaurs, pliosaurs and ichthyosaurs, as well as a number of invertebrate species.

<span class="mw-page-title-main">Stephen L. Brusatte</span> American paleontologist (born 1984)

Stephen Louis "Steve" Brusatte FRSE is an American paleontologist, author, and evolutionary biologist who specializes in the anatomy and evolution of dinosaurs. He was educated at the University of Chicago for his Bachelor's degree, at the University of Bristol for his Master's of Science on a Marshall Scholarship, and finally at the Columbia University for Master's in Philosophy and Doctorate. He is currently Professor of Palaeontology and Evolution at the University of Edinburgh. In April 2024, Brusatte was elected to fellowship of the Royal Society of Edinburgh.

<span class="mw-page-title-main">Marnes de Dives</span> Geological formation in Normandy, France

The Marnes de Dives is a geological formation in Normandy, France. It dates back to the upper part of the Callovian stage of the Middle Jurassic. And is partially equivalent to the Oxford Clay in England. It predominantly consists of ooidal marl, rich in pyrite and lignite, interbedded with thin limestone horizons. It is best exposed at the base of the Falaises des Vaches Noires as well as the foreshore at low tide. It is known for its fossils, notably those of ammonites, marine crocodiles and fragmentary remains of dinosaurs, mostly theropods.

<span class="mw-page-title-main">Isle of Skye</span> Island of the Inner Hebrides, Scotland

The Isle of Skye, or simply Skye, is the largest and northernmost of the major islands in the Inner Hebrides of Scotland. The island's peninsulas radiate from a mountainous hub dominated by the Cuillin, the rocky slopes of which provide some of the most dramatic mountain scenery in the country. Although Sgitheanach has been suggested to describe a winged shape, no definitive agreement exists as to the name's origin.

The Broadford Beds Formation is a Sinemurian geologic formation in western Scotland. An indeterminate partial tibia of a theropod dinosaur are among the fossils that have been recovered from the formation

<span class="mw-page-title-main">Valtos Sandstone Formation</span> Sandstone formation in Scotland

The Valtos Sandstone Formation is a Middle Jurassic (Bathonian) formation found in the Inner Hebrides of Scotland. It is the thickest member of the Great Estuarine Group. The lithology consists of sets of approximately 6 metre thick cross bedded sandstone, capped by thin shelly limestones containing bivalves of the genus Neomiodon Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.

<span class="mw-page-title-main">Irhazer Shale</span>

The Irhazer Shale or Irhazer II Formation is a Middle Jurassic geologic formation of the Irhazer Group in the Agadez Region of Niger. Fossil ornithopod tracks have been reported from the formation. The dinosaur Spinophorosaurus is known from the formation.

<span class="mw-page-title-main">Rhamphorhynchidae</span> Family of breviquartossan pterosaurs from the Jurassic period

Rhamphorhynchidae is a group of early pterosaurs named after Rhamphorhynchus, that lived in the Late Jurassic. The family Rhamphorhynchidae was named in 1870 by Harry Govier Seeley. Members of the group possess no more than 11 pairs of teeth in the rostrum, a deltopectoral crest that is constricted at the base but expanded at the distal end, and a bent phalange on the fifth toe.

<span class="mw-page-title-main">Great Estuarine Group</span>

The Great Estuarine Group is a sequence of Middle Jurassic sedimentary rocks deposited in the Inner Hebrides of Scotland. The sedimentary sequence was originally named the 'Great Estuarine Series' by geologist John Wesley Judd in 1878. Sedimentary outcrops occur on Skye, Raasay, Eigg and Muck. It comprises a series of shales, clays, silts, mudstones, and sandstones deposited in two drainage basins: the Inner Hebrides basin and the Sea of the Hebrides basin. The sediments are equivalent in age to the Inferior and Great Oolite Groups found in southern England.

<span class="mw-page-title-main">Bearreraig Sandstone Formation</span> Geological formation in Scotland

The Bearreraig Sandstone Formation is a geological formation in Scotland. It preserves fossils dating back to the lower to middle parts of the Jurassic period (Toarcian–Bajocian). The remains of the proximal portion of a right ulna and radius of an indeterminate thyreophoran dinosaur are known from the formation. The ichthyosaur Dearcmhara is also known from the formation.

<span class="mw-page-title-main">Duntulm Formation</span>

The Duntulm Formation is a sedimentary geologic formation deposited in the Inner Hebrides, Scotland. The formation was previously known as the 'Lower Ostrea Beds', and dates to the Bathonian stage of the Middle Jurassic. The formation is noted for its highly fossiliferous oyster beds, which compose of the species Praeexogyra hebridica. The sedimentary sequence also forms part of the Great Estuarine Group.

<span class="mw-page-title-main">Kilmaluag Formation</span> Geologic formation in Scotland

The Kilmaluag Formation is a Middle Jurassic geologic formation in Scotland. It was formerly known as the Ostracod Limestone for preserving an abundance of fossil freshwater/low salinity ostracods. Gastropods, bivalves, trace fossil burrows, and vertebrate fossil remains have also been recorded from the formation. Vertebrate fossils include fish, crocodylomorphs, mammals, small reptiles, amphibians, theropod and sauropod dinosaurs and pterosaurs.

Dearcmhara is a genus of marine reptile from the early to mid-Jurassic period around 170 million years ago, known from fossil remains found on the island of Skye in Scotland. The type species is Dearcmhara shawcrossi. Fragmentary fossil remains of the animal were discovered by an amateur fossil hunter in 1959 and were subsequently donated to a museum, but it was not until 2014 that a scientific research project determined that the fossils were of a previously unknown species.

Nicholas Campbell Fraser, known as Nicholas C. Fraser, is a British palaeontologist, academic, and museum curator. He specialises in the Triassic period and vertebrate palaeontology. Since 2007, he has been Keeper of Natural Sciences at the National Museums Scotland. He has been adjunct professor of geology at Virginia Tech since 1993 and at North Carolina State University since 2007.

<i>Dearc</i> Genus of rhamphorhynchine pterosaur

Dearc is a genus of large-bodied rhamphorhynchine pterosaur from the Middle Jurassic Lealt Shale Formation of Scotland. The holotype, a juvenile or subadult that was still actively growing, has an estimated wingspan of 2.5 to 3 meters, making it the largest flying animal of its time. This pushes the origin of large pterosaurs back significantly, as it was previously assumed that pterosaurs did not reach greater body sizes until the short-tailed pterodactyloid lineages of the Cretaceous. The genus contains a single species, Dearc sgiathanach ( ).

Michael Waldman is a British palaeontologist known for his work on fossil fish, mammals, and reptiles. He also discovered the globally important fossil site of Cladach a'Ghlinne, near Elgol on the Isle of Skye, Scotland. This site exposes the Kilmaluag Formation and provides a valuable record of Middle Jurassic ecosystems. During the 1970s he visited the site several times with fellow palaeontologist Robert Savage. The fossil turtle Eileanchelys waldmani was named after Michael in recognition of his notable contribution to palaeontology.

Ceoptera is an extinct genus of darwinopteran pterosaur from the Middle Jurassic Kilmaluag Formation of Scotland. The genus contains a single species, C. evansae, known from a partial skeleton. It is the only pterosaur from Kilmaluag Formation. Ceoptera represents the second pterosaur named from Scotland, after Dearc in 2022.

References