Fig. 1: An unusual cliffside exposure, a cross-section of a dinosaur footprint! An ornithopod stepped in wet mud. As the animal's great foot sank in, material was expressed upwards on either side, forming flame structures (not particularly clear but see purple mud visible here on the right side of the print). The print was then subsequently filled by overbank deposits. Pen for scale, length 15 cm. See Gale (2019, p.110) for an example of a giant sauropod print, similarly preserved.
"Rock of the Month #289, posted for July 2025" ---
Dinosaur tracks from the lower Cretaceous
The Isle of Wight is a large (384 km2), diamond-shaped island situated off the coast of central southern England. It is accessible from the mainland ports of Portsmouth, Southampton and Lymington, by ferries across the Solent, a broad waterway formed by Holocene sea level rise (Reid, 1913; Allen and Gibbard, 1993). The many beautiful cliffs and beaches display a wide range of fossils and interesting pebbles (Ellis, 1957; Anon, 1971). The island is notable for a complete Jurassic succession accessible in boreholes, as well as superb coastal exposures of Cretaceous and Palaeogene (early Tertiary) strata, all modified by Pyrenean, Icelandic mantle plume, and Alpine tectonism and later processes of Quaternary geomorphology.
The Wessex Formation of the lower Cretaceous Wealden Group (age circa 130 Ma) is displayed in the cliffs of the southwest and southeast coasts of the island. These strata are older than the iconic chalk cliffs, superbly displayed at intervals along the coast of southern Britain from Beer in Devon to Dover in Kent (see, e.g., Trueman, 1971). The Wealden vertebrate fauna incorporates some mighty dinosaurs, including the genus Iguanodon, first described in 1825, amongst Europe's most diverse dinosaur assemblage. Iguanodon grew as large as 10 metres in length, 4.5 tonnes in weight. The photographs shown here were taken on the cliff and beach in the Brook Bay area. The vertebrate fauna includes a vast diversity of smaller vertebrates (see contributions in Batten, 2011) and an interesting assemblage of crocodyliforms including large ambush predators and diminutive forms (Sweetman et al., 2014).
The Isle of Wight is highly significant in terms of Mesozoic and Cenozoic stratigraphy, palaeontology, and the history of Earth science. The stratigraphic outlines have been established long since, across generations of field trips and observations (e.g., Jukes-Brown, 1886; Wells and Kirkaldy, 1966; Wyse Jackson, 2007). Detailed descriptions may be found in Hopson and Farrant (2015) and the field guide of Gale and colleagues (2019).
Figs. 2-3: Casts of prints of giant 3-toed feet, which have been preserved as sandstone masses after the softer, clay-rich surrounding rocks weathered out of the cliff. Pen for scale, length 15 cm.
Acknowledgements
This modest note was made possible by a short but very enjoyable tour of the island led and hosted by Steve and Pru Sweetman, with logistics by Phil Handcock, as part of the second Oxford Geology (1973) reunion! Many thanks to all involved! Steve kindly provided a prompt and effective edit that greatly improved the tone and accuracy of the text.
It is also worth noting that no geological visit to the Isle of Wight would be complete without a visit to the Dinosaur Isle Museum at Sandown on the southeast coast of the island. Go there to see an Iguanodon skeleton and other remarkable fossils, the majority local, plus others from France and elsewhere.
REFERENCES
Allen,LG and Gibbard,PL (1993) Pleistocene evolution of the Solent river of southern England. Quaternary Science Reviews 12, 503-528.
Anon (1971) British Caenozoic Fossils. British Museum (Natural History), London, 4th edition, 132pp.
Batten,JD (editor) (2011) English Wealden Fossils. Palaeontological Association Field Guide to Fossils 14, 769 pp.
Ellis,C (1957) The Pebbles on the Beach. Faber and Faber Limited, London, 2nd edition, 163pp.
Gale,A (2019) The Isle of Wight. Geologists' Association Guide no.60, 6th edition, vi+174pp.
Hopson,PM and Farrant,AR (2015) Geology of the Isle of Wight. British Geological Survey, 164pp.
Jukes-Browne,AJ (1886) The Student's Handbook of Historical Geology. George Bell and Sons, Covent Garden, London, 597pp.
Reid,C (1913) Submerged Forests. Cambridge University Press, 129pp.
Sweetman,SC, Pedreira-Segade,U and Vidovic,SU (2014) A new bernissartiid crocodyliform from the Lower Cretaceous Wessex Formation (Wealden Group, Barremian) of the Isle of Wight, southern England. Acta Palaeontologica Polonica 60, 257-268.
Trueman,AE (1971) Geology and Scenery in England and Wales. Penguin Books Ltd, revision of 1949 original by Whittow,JB and Hardy,JR, 400pp.
Wells,AK and Kirkaldy,JF (1966) Outline of Historical Geology. Thomas Murby & Co., London, 6th edition, 533pp.
Wyse Jackson,PN (editor) (2007) Four Centuries of Geological Travel: The Search for Knowledge on Foot, Bicycle, Sledge and Camel. Geol.Soc.London Spec.Publ. 287, 415pp.
Graham Wilson, 29-30 June and 01 July 2025
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