“As much mud in the streets as if the waters had but newly retired from the face of the earth, and it would not be wonderful to meet a Megalosaurus, forty feet long or so, waddling like an elephantine lizard up Prospect Hill.”
So wrote Charles Dickens in his 1853 novel Bleak House, although of course his original text actually references Holborn Hill in London.
Yet few people are aware that the terrible dinosaur he names once roamed the land where Whitby’s streets now stand.
At seven metres in length, Megalosaurus was a terrifying cousin of Tyrannosaurus Rex and would stalk its prey on the wide river deltas that stretched across the region, from Whitby to the Humber.
“What would I suggest if you bumped into Megalosaurus on the streets of Whitby?” said palaeontologist Will Watts. “Run like hell.”
The dominant hunter in this area, Megalosaurus would feed on Stegosaurus or the giant sauropods which gathered at the river’s edge to drink.
Will added: “It was the apex predator, the top of the tree. The only things that were safe were the things that ran faster than it.”
With legs 10 feet in length, the prehistoric hunter could easily outrun a human.
Sat beside a replica Allosaurus skull, which would have been similar to Megalosaurus in both size and appearance, Will Watts describes the landscape which would have greeted a visitor to the Whitby area 150 million years ago.
At that time Whitby was roughly where North Africa is today, gradually moving northwards.
The supercontinent of Gondwana was starting to pull apart, but the Atlantic Ocean had not even begun to open up and the Himalayan mountain range would not start to rise from the collision of India and Asia for another 100 million years.
With an average temperature five degrees warmer than today, Whitby was a subtropical oasis.
“The landscape was pretty much dominated by massive rivers,” said Will. “There were hills to the north, where Middlesbrough is and a shallow sea where Hull is.
The Yorkshire coast formed a huge delta where Mississippi-sized rivers deposited layers of mud for millions of years - which eventually hardened to form the layer of Jurassic sandstone which can be seen high up in the cliffs around Whitby.
On the banks of these rivers was lush vegetation - but no grass or flowering plants, as they had not evolved yet.
“When you have lots of vegetation, something is going to eat it,” said Will, who brings the prehistoric world into classrooms around the region through his company, Hidden Horizons.
Along the Yorkshire coast have been discovered 25 different types of footprint, representing all the major dinosaur groups. They range from large theropods, such as Megalosaurus, to small carnivores or large herbivores like Stegosaurus or the sauropod Diplodocus.
Although these ‘trace’ fossils are common, actual finds of dinosaur bones are extremely rare on the Yorkshire coast, but they do occasionally occur.
There have been only 25 recorded dinosaur bones recovered in this area in the last 200 years, and these have been poor quality as the high acid content of water within the sandstone rapidly dissolves bone.
“Fossils are miraculous,” said Will, explaining that for a dinosaur bone to be discovered, over the 100 million years since the animal died, a series of against-the-odds events have to take place.
He added: “Using fossils to reconstruct what the world was like back then is like trying to rewrite Shakespeare when you have only got one letter from one word on every tenth page.”
So there is a huge amount of educated guesswork that has to take place.
A good place to start is the habitat ancient animals would have lived in, which can be firmly understood.
Through sedimentation, different habitats lay down various types of rock.
The black shale found along our coast is evidence of the ancient sea which once drowned this area. It is in this rock that Whitby’s most famous fossils, ichthyosaurs and ammonites, are found.
Younger than this, and therefore higher in the cliff around Whitby - out of the reach of most fossil hunters - is a layer of Jurassic sandstone, and it is in this that Whitby’s dinosaurs lie in wait.
This knowledge about the age of rocks was uncovered by pioneering geologists, many of whom used these very rocks around Whitby to shape the modern world.
“It’s amazing how many people locally are still unaware of this fantastic heritage we have,” said Will. “It is enjoyable to be able to take people on that journey and allow them to discover the history of the Whitby coast for themselves.”
So Whitby was once filled with giants that could eat a human in one gulp, and maybe we should be thankful the only animals we have to worry about are low-flying gulls.
But Jurassic sandstone is a popular building material in this area and it may be that there is already a dinosaur hidden in your house.