Hornsleasow Quarry (Jurassic of the United Kingdom)

Also known as Snowshill Quarry

Where: England, United Kingdom (52.0° N, 1.8° W: paleocoordinates 41.6° N, 8.6° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Zigzagiceras zigzag zone, Chipping Norton Limestone Formation (Great Oolite Group), Early/Lower Bathonian (167.7 - 164.7 Ma)

• "Hornsleasow Clay Unit" placed between Chipping Norton Member (above) and Hook Norton Member (below). Upper part of unit is the "Green Clay" and lower part is the "Grey Clay". From the macrescens Subzone of the zigzag Zone

• bed-level stratigraphic resolution

Environment/lithology: karst; bioturbated, pebbly, carbonaceous claystone and claystone

• Clay units were deposited into the karstic surface of the Hook Norton Member. Clay deposition involved low paleocurrent activity and increasingly anoxic conditions. The unit "is interpreted as a paleosol. The depositional environment...is one of marshy, low-pH type. The partially decayed organic material within this deposit suggests relatively reducing conditions, and the presence of pyrolusite (MnO2)...is suggestive of bog or lake deposition...salinity was low to moderate...The Grey Clay is a waterlogged, boggy paleosol developing within a freshwater to brackish-water pond. The absence of dispersed kerogen indicates a low-energy depositional environment, with little fluvial influence...The Green Clay is also interpreted as a paleosol, deposited under more oxidizing, high-pH conditions.
• Primary (Grey Clay): "matrix-supported, but contains large, irregularu subrounded limestone cobbles (concentrated in the basal portion, which is interpreted as a regolith), with associated lime and lime-fraction silica sand. The clay is smectitic, with a high organic content, and it contains much partially lignitized wood...finely laminated. This lamination has been somewhat disrupted, possibly by bioturbation."

•Secondary (Green Clay): "more homogenous than the Grey Clay. Limestone clasts and sand make up only 3 percent of the composition by weight. The deposit has more silica and sand and is an illite/chlorite clay. Vertical rootlets pervade the layer, extending from the mud-cracked, upper surface...into the underlying Grey Clay...The plant material is somewhat oxidized."

Size classes: macrofossils, mesofossils, microfossils

Collected by K. Gardner in 1987

Collection methods: bulk, surface (in situ), sieve,

Primary reference: S. J. Metcalf and R. J. Walker. 1994. A new Bathonian microvertebrate locality in the English Midlands. In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods, edited by N. C. Fraser and H.-D. Sues. Cambridge University Press, Cambridge 322-331 [M. Carrano/M. Carrano/J. Alroy]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 31054: authorized by Matthew Carrano, entered by Matthew Carrano on 09.04.2003, edited by Kaitlin Maguire and Richard Butler

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
cf. Alocodon sp.3
"hypsilophodontid similar to Alocodon sp."
Nodosariata
 Robertinida - Epistominidae
Foraminifera
 Trochamminacea - Trochamminidae
Lycopodiopsida
 Selaginellales -
Densoisporites velatus3 Dettmann 1963 clubmoss
Algae
  - Botryococcaceae
Botryococcus braunii3 Kutzing 1849
 Coniferales - Podocarpaceae
Callialasporites sp.3 Sukh-Dev 1961 podocarp
Anthozoa
  -
Anthozoa indet.3 Ehrenberg 1834
"corals"
Gastropoda
 Architaenioglossa - Viviparidae
 Sorbeoconcha - Naticidae
Naticidae indet.3 Guilding 1834 moon snail
 Heterostropha - Valvatidae
Bivalvia
  -
Bivalvia indet.3 Linnaeus 1758 clam
 Pectinida - Limidae
? Plagiostoma sp.3 Sowerby 1814 file clam
 Ostreida - Gryphaeidae
Praeexogyra sp.3 Charles 1952 oyster
Deuteropoda
  -
Ostracoda indet.3 Latreille 1802 ostracod
Echinoidea
  -
Echinoidea indet.3 Leske 1778 sea urchin
Chondrichthyes
 Hybodontiformes - Acrodontidae
Asteracanthus sp.3 Agassiz 1836 elasmobranch
GLRCM G.50031
Amphibia
 Salientia -
? Anura indet. Fischer von Waldheim 1813 frog
 Caudata -
Caudata indet.3 salamander
"salamanders"
Caudata "indet. B"1 salamander
? Marmorerpeton sp.3 Evans et al. 1988 salamander
GLRCM G.60406
 Temnospondyli - Albanerpetontidae
Albanerpetontidae indet.2 Fox and Naylor 1982 tetrapod
Osteichthyes
 Therapsida -
 Therapsida - Tritylodontidae
Tritylodontidae indet.1 Cope 1884 mammaliamorph
Stereognathus ooliticus4 Charlesworth 1854 mammaliamorph
GLRCM G.53809
Mammalia
  -
Mammalia indet.1 Linnaeus 1758 mammal
 Allotheria -
Multituberculata indet.3 Cope 1884 multituberculate
 Pantotheria -
Eupantotheria indet.3 Kermack and Musset 1958 mammal
GLRCM G.66570; "eupantotheres"
? Eupantotheria indet.3 Kermack and Musset 1958 mammal
GLRCM G.66856
Osteichthyes
 Cynodontia -
Docodonta indet.3 Kretzoi 1946 dodocont
Reptilia
 Testudines -
Testudines indet.3 Batsch 1788 turtle
GLRCM G.66759
 Squamata -
aff. Squamata indet.3 squamates
"squamate affinites"
 Loricata -
Crocodylia indet.3 crocodilian
GLRCM G.55545, 50002
 Loricata - Goniopholididae
"Goniopholidae indet." = Goniopholididae3
"Goniopholidae indet." = Goniopholididae3 Cope 1875 crocodilian
"goniopholids"
 Loricata - Teleosauridae
? Teleosauridae indet.3 Geoffroy 1831 marine crocodile
 Ornithischia - Fabrosauridae
? Fabrosauridae indet.1 Galton 1972 ornithischian
GLRCM G.53264; "fabrosaurid similar to Phyllodon sp."
 Ornithischia -
? Stegosauria indet.3 ornithischian
GLRCM G.64020
 Ornithischia - Hypsilophodontidae
Hypsilophodontidae indet.1 hypsilophodontid
"hypsilophodontid similar to Alocodon sp."
 Theropoda -
Coelurosauria indet.1 Huene 1914 coelurosaur
GLRCM G.51422; small theropods, possibly maniraptoran or dromaeosaurid
 Theropoda - Megalosauridae
Megalosaurus sp.3 Parkinson 1822 tetanuran theropod
GLRCM G.66742
 Theropoda -
 Saurischia -
Cetiosaurus sp.3 Owen 1841 sauropod
GLRCM G.50051
 Pterosauria -
Pterosauria indet. Kaup 1834 pterosaur
Pterosauria indet.5 Kaup 1834 pterosaur
 Pterosauria - Rhamphorhynchidae
Rhamphocephalus sp.5 Seeley 1880 pterosaur
GLRCM G.66839; "rhamphorhynchoid"
 Eosuchia -
 Lepidosauria -
 Choristodera -
Choristodera indet.1 choristodere
 Choristodera - Cteniogenyidae
cf. Cteniogenys sp. Gilmore 1928 choristodere
GLRCM G.66855, 51749
Actinopteri
 Pycnodontiformes - Pycnodontidae
Pycnodontidae indet.3 Agassiz 1833
 Lepisosteiformes -
Lepidotes sp.3 Agassiz 1832 gar
GLRCM G.50001