Saturday, 30 August 2014

Carboniferous Calamites

On a recent visit to Newcastle, I managed to make a visit to Seaton Sluice. This sadly named village has some interesting outcrops of carboniferous rocks as well as a rather quaint looking harbour which, I presume, is the basis for the word 'sluice'. There's also a pretty good fish and chip shop on the main road there but beware, the fish portions are enormous.

The fossil that I managed to find there is that of a couple of segments of a calamites stem from about 309 mya. Calamites are horsetails but unlike their modern counterparts, these were tree like and grew to around 30 metres. The stems of calamites, like their modern counterparts were hollow, rather like bamboo for example (unrelated). These hollow stems tended to fill with material to form , over the millions of years, casts of the inside of the plant. I believe that the fossil that I collected  is of this kind and shows the internal ribbing of the stem. There were a number of splendid fossils of the stems or possibly roots that were visible in the rocks and I have  included photographs of those as well as they look splendid and will probably be destroyed by wave action over the next several winters.

The first image is longitudinal showing the ribbing and the two segments. The second is transverse showing the infill and the vestiges of the outer layer on the far left.The third  is the reverse of the fossil and matrix showing additional stems.



The following images are taken from the rocks in situ and just below a walkway and steps. You can see fairly extensive stem, root or rhizomes in the matrix. Notice also that many of the  pieces are smooth rather than ribbed and  mostly do not appear to be segmented. You can also see the relative thickness of the stem wall in the third of this set of images (which sadly is a little out of focus).

These were all located in one outcrop and all within a metre of each other. In the short amount of time afforded to me (it was an hour from high tide and the waves were splashing up at my back) I didn't find any other similar fossils in the vicinity. perhaps a more leisurely search would have revealed better evidence

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