The Netherlands appears to have much older pieces of earth than was thought, reports research organization TNO on Thursday.

330 million years old rock in the Heimans quarry in South Limburg has so far been labeled as the 'oldest part of the Netherlands', but in Kortgene in Zeeland, rock that is about 420 million years old has surfaced.

No new drilling has taken place to find the rock, says geologist Sander Houben on behalf of the Geological Service of the Netherlands (GDN).

For the study, pieces of rock that were exposed during a drilling in 1982 were re-examined.

"We have now been able to take a good look at the fossil content for the first time and determine the age with certainty," says Houben.

"Through the microscope, fossil remains of primitive primeval plants, which settled on land more than 400 million years ago, became visible," he explains.

The piece of earth comes from an old mountain ridge that lies close to the earth's surface and extends into the Ardennes.

The ridge was created some time after a collision of two continents, TNO writes.

The sediments that were deposited at the time have been found in the fossil remains.

'Small but important piece of the puzzle solved'

Comparable pieces of rock from the south side of the ridge are said to have been excavated more often in France and Belgium and better researched.

According to Houben, for the first time a piece of earth can be so well documented in the Netherlands.

In 420 million years, the rock has survived four mass extinctions, Houben continues.

The geologist says that "a small but important piece of the puzzle of the Dutch subsurface" has been solved.

Geologists already assumed that in the southwest of the country, the oldest pieces of rock would be closest to the surface.

The oldest piece of earth in the world is about 4.4 billion years old.

That piece of rock is said to have formed 160 million years after the formation of the earth.