Head of 330 million-year-old great white shark-sized beast found in wall of cave

Despite being far away from the ocean, fossils suggest the Mammoth Cave National Park in Kentucky was once full of sharks.

The remains of around 15 to 20 different species of shark have been found in the cave, including a great white-sized monster that's sticking out of a wall.

Apparently the fossils are "a brand new record of sharks from a particular layer of time."

These sharks would have lived around 330 million years ago during the Late Mississippian geologic time period, according to 9 News.

It was when most of North America was full of oceans.

When these sharks died their bodies became covered in sediment that turned into limestone and then the cave formed, according to palaeontologist John-Paul Hodnett.

Mr Hodnett said: "There's hardly ever any record of sharks from a particular layer of time."

Mammoth Cave scientists Rick Olson and Rick Toomey who were mapping part of the cave when they spotted shark fossils, according to Vincent Santucci, a senior palaeontologist in the National Park Service.

Photos showed loads of shark teeth and cartilage that might be a shark's skeleton.

Mr Hodnett added: "That's pretty rare because cartilage is softer than bone so it's not often preserved."

Then when Mr Hodnett visited the caves last November he realised they may have found something much bigger than what he originally thought.

"It turns out is actually not a skeleton, it is actually just parts of the head. And the head itself is pretty big," he explained.

"You can see the part of the shark's jaw where it would have attached to the skull and the end that would have been its chin."

Part of a species called Saivodus striatus, only part of the jaw was visible, but it's estimated to have been 76cm long.

The whole animal was probably about the size of a modern great white shark, around five to seven metres long.

Mr Hodnett continued: "Caves are a very special environment, so it's not ideal to be removing big chunks of rock out of it and damaging the internal environment by doing this.

"We literally just scratched the surface, and the sharks are just coming out from that scratch.

"So, hopefully, with more field work, we'll get another good batch of specimens to kind of help get at least some more rich diversity."

Scientists have to crawl on their hands and knees for around a quarter of a mile to reach the fossils.

Yet it's a definite breakthrough as most of the fossil record from the Late Mississippian period has been found in Europe so far, so it should answer lots of questions about what was happening in North America at that time.