Great excitement last night. The Race Marshal had gone off with her fishing rod and came back with a chimaera, a ghost shark – caught off the pier in Seattle. She cooked the fillets in butter and a little chilli and it was ok – a gelatinous texture not unlike monkfish. Normally, these fish are only found down in the deep – but the Puget Sound has a shallow water variety, the spotted ratfish as it is called. They are a very non-endangered species – not fished commercially and possessed of spines poisonous enough to deter the omni-voracious harbour seals.

The species was first identified for Europeans in an 1839 book, The Zoology of Captain Beechey’s Voyage to the Pacific and Behring’s Straits performed in His Majesty’s Ship Blossom, by two Englishmen – Edward Turner Bennett and George Tradescant Lay. Both were eminent Victorian naturalists: Bennett had been involved in founding London Zoo, and Lay has a genus of daisies – Layia – named after him. His ‘tidy tips’ daisies are endemic to north-west America. After his voyage of discovery with Captain Beechy, Lay went on to serve as a missionary in China, ending up as British consul in Amoy, where he died of a fever in 1845.

But the history of Lay and Bennett is a trifle compared to the fish they named. The Hydrolagus colliei (which they named in honour of another eminent Victorian naturalist) can trace its ancestry back 400 million years – a genuine prehistoric survivor along with lice, coelacanths and horsetails. It is remarkable that anything survived the multiplicity of extinction events and geological and environmental upheavals over the millions of years of life on our planet.

Few did – so many species have risen and gone extinct. Many will never be known but, at least where the animal had a skeleton, palaeontologists have been able to uncover something of their nature. The Ashfall State History Park in Nebraska, for example, is extraordinary in its presentation of the American rhino. From the walkways over the excavation site, you can look down at a bas relief of perfect skeletons – rhinos lying over horses, camels, three species of turtle, wading birds, a type of hawk, a sabre-toothed musk deer and a bone-crushing dog.

Their remains are perfect because of the way they died. Twelve million years ago the volcanic bulge that now sits below Yellowstone National Park was more to the west – 400 miles away, near Boise in Idaho. There is constant anxiety that one day the bulge under Yellowstone will push through in a devastating explosion – which is what happened in the late Miocene.

This supervolcano hurled up tons of lava and suffocating ash. As the plume of fine dust spread downwind, lungs filled, choking first the smaller animals and then the larger, who collapsed on top of them. The ash buried the corpses so softly that their frames were not flattened into the two dimensions of most rock-bound fossils. So, today, you can see what was a waterhole on the American savanna surrounded by the animals and birds there at a moment in prehistoric time. It is a unique spectacle.

Discovery of this national treasure was through the good fortune of Michael Voorhies – now Professor Emeritus of Earth and Atmospheric Sciences, University of Nebraska at Lincoln. (The bone-crushing dog of the Miocene – the Cynarctus voorhiesi , whose bite marks are found on some of the skeletons – is named after him). On a summer’s evening in 1971, he and his geologist wife, Jane, were compiling a map of the terrain of Antelope County in Nebraska. Heavy rain had washed away soil at the edge of a gully and exposed the skull of what Professor Voorhies recognised as a juvenile Teleoceras. He recalls that he ‘scraped about a bit’ and realised that the whole of the rhino’s skeleton was intact – and that there might be many more to be found preserved in the soft volcanic ash.

His quick understanding of the treasures hidden here [1] – and his determination that the site should be properly excavated and protected – has made Ashfall one of the most extraordinary fossil finds on the planet. The films below will give you a little tour.

SUGGESTED LINKS

Professor Voorhies talks about the significance of Ashfall – https://youtu.be/DxlCd5qGBeI

Ashfall State Historical Park – https://youtu.be/tqXu9AUu914

The extraordinary chimaera – https://youtu.be/asQhHT_09HM

SOURCES
[1] National Geographic Society Research Reports Volume 19 p.671 A Miocene Rhinoceros Herd Buried in Volcanic Ash Grant Recipient: Michael R. Voorhies, Division of Vertebrate Paleontology, University of Nebraska State Museum, Lincoln, Nebraska.

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