Don’t you love clickbait, but there’s more than a grain of truth here. Predatory fish such as roach and pike do lurk in the Warwickshire Grand Union, but the area also contains evidence of ancient sharks that swarmed in a long-lost lake.
Back to the 19th century
Let’s briefly go back to the 19th century, when canal-side quarries at Shrewley were being dug into the local Arden Sandstone as a source of building stone. The quarries have long gone, but the layers of sandstone can still be seen in the banks of the Shrewley canal cutting which is a geological Site of Special Scientific Interest.
Because the quarried rock was dug by hand, any fossils within the rock layers were spotted by quarry workers and put aside. The latter part of the 19th century was the heyday of the Warwickshire Natural History and Archaeological Society, who were steadily amassing a comprehensive collection of Warwickshire’s different rocks and fossils. The Reverend Peter Bellinger Brodie, the society’s Honorary Curator, was especially instrumental in this process and many of his specimens can still be found in Warwickshire Museum’s collection today, which grew from that of the ‘old society’. Brodie often visited the Shrewley quarries, especially during his later years, as they were close to Warwick and the museum.
What’s in 12 million years?
Fossils had long been known from the sandstones of Warwick, especially the quarry at Coten End, which is also preserved today as a Site of Special Scientific Interest. The Warwick sandstones are roughly 245 million years in age, dating back to the early part of what geologists refer to as the Triassic Period. The fossils include remains of giant extinct salamanders and small herbivorous reptiles known as rhynchosaurs, attesting to life on hot subtropical river floodplains, before the age of the dinosaurs.
However, the Arden Sandstone at Shrewley is subtly different. Though still belonging to the Triassic Period, it is roughly 12 million years younger than the Warwick stone. It also looks different – thinly layered and pale grey in colour – rather than the more massive, buff-coloured rock of Coten End and Warwick’s older buildings. This reflects the Arden Sandstone’s origins in the rippled shallows of a long-lost Triassic lake which once covered the area, rather than the product of rivers in flood. And this origin is reflected by the fossils collected by Reverend Brodie at Shrewley, preserved in the museum collections. We find the fin-spines of sharks rather than bones of salamanders, and sandstone surfaces covered in tiny footprints where reptiles grubbed around the debris fringing the lake’s shore. We now know that the fossilised fin spines belonged to freshwater sharks, quite small at less than a metre long, but armed with sharp teeth for grabbing fish and other prey. At times the sharks must have swarmed in the shallows of the Shrewley lake, a veritable Triassic feeding frenzy.
A group of feeding sharks
A Shrewley shark fin spine featured in our 2024-2025 exhibition at the Market Hall Museum, Tales From The Riverbank. To bring the ancient Triassic scene to life, we commissioned palaeo-artist Jack Wood to illustrate a group of feeding sharks, along the shore of our Shrewley lake nearly a quarter of a billion years ago. We hope you like it as much as we do – a window into Warwickshire’s past.
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