Sunday, November 18, 2012

Rock of Ages



The Durham coast isn’t a top destination for fossil hunters, who find richer pickings further south under the crumbling cliffs around Whitby, but occasionally interesting fossils do turn up on our beaches. I found one has week, on Blast beach just south of Seaham, which gave a tantalising glimpse of how the landscape might have looked three hundred million years ago.




















Blast beach was formerly a site for dumping colliery waste but in recent years the magnificent Turning the Tide project has made great strides in restoring this coastline to its former, pre-industrial glory. There are still large boulders on the beach that were transported with colliery debris and it was when I split one of these that I found the remains of a plant that had been embedded in the rock for three hundred million years.   The compressed, jointed stems, now turned to stone, belonged to a giant horsetail.If you double-click for a larger image you can see that there are two reasonably intact compressed fossil stems here - one running at an 11 'o'clock to five o'clock angle and the other running eight o'clock to two o'clock.


Back in the Carboniferous, when the coal measures and the land mass that is now Britain was nearer the equator, these strange plants formed tropical, forests in swamps that would have been home to early amphibians and giant dragonflies.

Horsestails still exist today, as 'living fossils', but are a pale shadow of their extinct ancestors. Gardeners are familiar with the field horsetail, which is a troublesome weed but only grows about a foot tall. Today specimens of the great horsetail, the largest horsetail species that grows in damp places along this coast, reach a height of about five feet. Judging by the width of the fragment of fossil stem that I found, this long-extinct plant must have been at least four times as tall. Larger fossils that have been found indicate that these ancient plants sometimes grew to a height of sixty feet or more. 





12 comments:

  1. Thanks for visting my blog - yours seems to have passed me by which is pity for it looks excellent. I remember holiday son the Durham as child, at Crimdon Dene of all places!

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  2. Oh Phil, so you now have a museum specimen in your possesion. Congratulations. And you did great in identifying what left that imprint on the rock!

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  3. Horsetails aren't so common here in the US. I always get a kick out of finding them in the wild.

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  4. Though I would never have recognised the fossil I can well believe Horsetails have been around for a while. There were lots of them at Winston alongside the river. They always took me back to my prehistoric days.

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  5. What an exciting find! I would never have recognized it as a fossil.

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  6. A great find. I only ever found ammonite and trilobite fossils around the Whitby / Robin Hoods Bay area of the coast. Never any plant life.

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  7. Hi Mark, Good to make contact with you - I enjoy reading your blog. All the best,
    Phil

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  8. Hi Andrea, We've got a garden full of fossils that we've collected along this coast at various times..

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  9. Hi Wilma, I vaguely recall reading that there were masses of horsetails along some stretches of the Mississippi ... but I might have imagined that!

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  10. Hi Adrian, it's amazing that they are more or less unchanged, after 300 million years...!

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  11. Hi lotusleaf, I think it was the low angle of the winter sun, that threw the fossil into relief on the rock surface..

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  12. Hi John, We used to take our kids fossil hunting under the cliffs at Port Mulgrave, just north of Whitby...

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