A Brief History of the Hanover Point Dinosaur Footprints

Article by: Harry T. Jones
Edited by: J. D. Dixon

Compton Bay, with Hanover Point visible at the far right of the cliffs. Image from Visit Isle of Wight (2021).

To the south of England lies its largest island, the Isle of Wight. This diamond-shaped island is geologically renowned for its rock strata from the Cretaceous and Paleogene periods due to their visibility in the island’s coastal cliffs. Exposures of these rocks follow a north/south divide, with the south of the island comprising older Cretaceous strata and the north comprising younger Paleogene strata. Hanover Point is on the Isle of Wight’s south-west coast and represents the island’s oldest rocks of the Wealden Group, dating from the Barremian Stage of the Lower Cretaceous.

The location and generalised stratigraphy of the Isle of Wight. Hanover Point is highlighted on the map, with its approximate age circled on the stratigraphic log. Modified from Lockwood et al. (2014) by Harry T. Jones.

Hanover Point is one of several localities that have earned the Isle of Wight its sobriquet “Dinosaur Island”. This site alone is home to over 150 dinosaur footprints, most of which have been preserved as natural casts within the Wessex Formation. Since 2004, Hanover Point has been part of an extended Site of Special Scientific Interest (SSSI) because of its biological and geological significance. The area is also National Trust land, so it is illegal to remove casts without permission or use tools such as hammers.

The majority of the Hanover Point footprints were made by ornithopods, historically attributed to Iguanodon. These footprint ichnofossils (trace fossils) were first documented in 1847 by Gideon Mantell, who called them “concretions”. It was not until 1853 that the connection was made between these “concretions” and dinosaurs, after Samuel Beckles showed Richard Owen an almost complete hindlimb from a juvenile Iguanodon found on the Isle of Wight. This allowed Owen to match the foot to the footprint, and likely marked the birth of footprint ichnology as a scientific study.

An adult and juvenile Iguanodon by John Sibbick.

When dinosaurs made these footprints over 125 million years ago, the climate was variable and Mediterranean-like. The palaeoenvironment of the Hanover Point area is interpreted as a sequence of alluvial (river) meander plains which covered the Wessex Sub-basin of southern England, with forests covering higher ground to the north. The highly sinuous rivers were surrounded by short-lived, seasonal lakes and ponds within the basin. A likely annual transition from hot-drier to cool-wetter weather meant that forest fires and flooding were common, washing plant material into this basin. One flash-flood event produced the ‘pine raft’, a plant debris bed exposed at low tide which comprises fossilised conifer trunks that became stranded on a point bar.

The ‘pine raft’ underlies the thick sandstone bed from which the footprints originate. The underside of this bed forms a natural cast of a heavily ‘dinoturbated’ surface. The fact that footprints are found at different levels suggests the area was teeming with dinosaurs, even if only seasonally. After the dinosaurs left their mark in the mud, a flood event caused the river to break a levee and deposit sediment onto the floodplain, forming a crevasse-splay. This event infilled the underlying footprints with sandy sediment and formed the sandstone bed in which the footprint casts are found. Another plant debris bed overlies this sandstone and contains plant and vertebrate fossils, including crocodilian, turtle, and dinosaur bones (such as Iguanodon). The sandstone and plant debris beds are exposed in accessible sections at Hanover Point, and some footprint casts can be seen in situ before they are fully eroded out of these exposed rock faces.

A) exposed Hanover Point beds (I, ornithopod footprint natural cast; II, dinoturbated underside; III, crevasse-splay sandstone; IV, plant debris bed; V, Wealden Mudstone). B) more exposed beds at Hanover Point with an in situ footprint cast circled. C) natural cast of a possible theropod footprint partially eroded from the sandstone of B. Scale bar = 15 cm. Image A taken from Lockwood et al. (2014); images B and C by Harry T. Jones.

The footprints became fossilised over millions of years. The muddy footprints acted as natural moulds and the sand that infilled them was eventually compacted and lithified until it became the sandstone we see today. As tectonic processes later exposed these strata at the surface, erosional processes broke down the host rocks and revealed the footprint casts that now fall onto the beach. The undersides of several ornithopod casts seem to exhibit irregular ripple marks, suggesting the original footprint was particularly shallow and formed in water. Many casts also show layering indicative of cross-stratification, indicating episodic infilling, likely caused by repeated flooding events. Some footprints exist as the ‘true track’, the original impression left in the floodplain mud. These prints occur on a mudstone bed on the foreshore of the wave-cut platform off Hanover Point (visible at low tide).

The types of fossil footprint tracks that can be produced from a single step. Taken from Vitkus et al.

The majority of the Hanover Point footprints have a tridactyl (three-toed) morphology. Most of these are attributed to ornithopods (herbivores that could move on two or four legs), due to their generally relatively rounded shape with three stubby toes. Some are interpreted as theropod prints (mostly carnivorous bipeds), as these are more pointed and have thinner digits. Fewer morphologically-different prints were made by thyreophorans (mostly quadrupedal, armoured herbivores) and may appear more rectangular. However, variation in all three footprint types indicates more research is needed to understand the dynamics of footprint formation.

A) a photogrammetric image of an ornithopod footprint cast with manus (front foot) atop pes (hindfoot). B) a drawing of the cast in image A. C) a theropod footprint. D) a natural cast of a presumed thyreophoran pes. E) typical track morphologies for ornithopods, theropods, and thyreophorans (ankylosaurs) along with their presumed trackmakers. Compiled by Harry T. Jones: Images A-D from Lockwood et al. (2014); Image E adapted from Martin (2005).
A selection of footprints from Hanover Point. Scale bar = 15 cm. A) ornithopod print with one toe eroded away. B) ornithopod print. C) ornithopod print with segmented pads. D) ornithopod print. E). a trackway of three sequential ornithopod prints on a wave-cut platform. F) ornithopod print with another cast superimposed. G) Image F with focus on superimposed print. H) a potential theropod footprint eroded. Images by Harry T. Jones; Image E from Lockwood et al. (2014).

As it is difficult to correlate a footprint with an exact species, morphologically similar prints are assigned their own ‘ichnogenus’. Most of the large ornithopod footprints at Hanover Point best match the ichnogenera Caririchnium and Amblydactylus. When accompanied by local body fossils, now in the Isle of Wight County Museums Service (IWCMS) collection, this information can be used to deduce that the main trackmakers were likely Iguanodon bernissartensis and Mantellisaurus atherfieldensis. This relatively low diversity may be a result of a preservational or taphonomic bias or low productivity of vegetation on the alluvial floodplain. Iguanodontids at least occasionally formed herds so may have passed through this environment together as part of a seasonal migration. Smaller ornithopod casts being less common may be due to preservational, erosional, or sampling biases or indicative of a lower diversity of smaller animals at the time of deposition.

Mantellisaurus atherfieldensis, believed to be semi-quadrupedal, by Steveoc 86 (2019).

Hanover Point and Compton Bay are well worth a visit should you ever find yourself on the Isle of Wight. Many footprints have already been lost to the sea by erosion as well as through illicit collection, but it is likely that many more will be revealed in years to come. In any case, searching for the footprints as they are today and exploring the wave-cut platform when safe to do so is an enjoyable experience for all. You may even come across a print or fossil that no one has seen before! Until then, you can enjoy a selection of footprints from this area in 3D through the website Sketchfab, including the photogrammetric model below.

A 3D photogrammetric model of a theropod footprint cast from Hanover Point by Harry T. Jones (2021).

Image References
[1] Compton Bay and Hanover Point from Visit Isle of Wight (2021).
[2] Isle of Wight and Hanover Point map and stratigraphy modified from Lockwood et al. (2014) by Harry T. Jones.
[3] Iguanodon walking with young by John Sibbick.
[4] A-C by Lockwood et al. (2014) and Harry T. Jones.
[5] Tracks that can be produced from a single step. Taken from Vitkus et al.
[6] Compiled by Harry T. Jones: Images A-D from Lockwood et al. (2014); Image E adapted from Martin (2005).
[7] A-E compiled by Harry T. Jones from Lockwood et al. (2014) and Martin (2005).
[8] Mantellisaurus atherfieldensis by Steveoc 86 (2019).
[9] Hanover Point Theropod Dinosaur Footprint by Harry T. Jones (2021).

Information References and Further Sources
[1] Benton, M. J., and Spencer, P. S. (2012). Fossil Reptiles of Great Britain. (2nd ed.). Berlin, Germany: Springer.
[2] Dinosaur Isle. (Unknown). Type, Cited and Figured Specimens. Accessed 14th October 2021. Click Here.
[3] DinoWight. (Unknown). Dinosaur Footprints. Accessed 14th October 2021. Click Here.
[4] Downes, J. (2021). The Isle of Wight: Landscape and Geology. Wiltshire, UK: The Crowood Press. 
[5] Fossil Hunters. (2021). Defining Dinosaurs: Pace Angulation 180 Animal. Accessed 21st October 2021. Click Here.
[6] Hooker, J., and Sweetman, S. (2009). ‘Early Cretaceous and Paleogene Vertebrate Localities of the Isle of Wight, Southern England: A Field Trip Guide for the Society of Vertebrate Paleontology’, Society of Vertebrate Paleontology 69th Annual Meeting, pp. 40-41. Accessed 14th October 2021. Click Here.
[7] Hopson, P. (2011). ‘The geological history of the Isle of Wight: an overview of the ‘diamond in Britain’s geological crown’’, Proceedings of the Geologists’ Association, 122 (5), pp. 745-763. Accessed 14th October 2021. Click Here.
[8] Insole, A. N., and Hutt, S. (1994). ‘The palaeoecology of the dinosaurs of the Wessex Formation (Wealden Group, Early Cretaceous), Isle of Wight, Southern England’, Zoological Journal of the Linnean Society, 112 (1-2), pp. 197-215. Accessed 14th October 2021. Click Here.
[9] Lockwood, J. A. F., Lockley, M. G., and Pond, S. (2014). ‘A review of footprints from the Wessex Formation (Wealden Group, Lower Cretaceous) at Hanover Point, the Isle of Wight, southern England’, Biological Journal of the Linnean Society, 113 (3), pp. 707-720. Accessed 14th October 2021. Click Here.
[10] Martin, A. J. (2005). Introduction to the Study of Dinosaurs. (2nd ed.). Wiley-Blackwell.
[11] National Trust. (Unknown). Searching for fossils around Compton Bay. Accessed 14th October 2021. Click Here.
[12] Natural England. (2003). Compton Chine to Steephill Cove SSSI Report. Accessed 15th October 2021. Click Here.
[13] Pond, S., Lockley, M. G., Lockwood, J. A. F., Breithaupt, B. H., and Matthews, N. A. (2014). ‘Tracking Dinosaurs on the Isle of Wight: a review of tracks, sites, and current research’, Biological Journal of the Linnean Society, 113 (3), pp. 737-757. Accessed 14th October 2021. Click Here.
[14] Visit Isle of Wight. (2021). Compton Bay. Accessed 14th October 2021. Click Here.
[15] Vitkus, A., Chin, K., and Lockley, M. (Unknown). Fossil footprints through geologic time: I. How tracks are preserved. Accessed 17th October 2021. Click Here.