tqb
Enthusiastic fossilologist
Posts: 111
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Post by tqb on Sept 12, 2011 10:02:26 GMT -5
Hi, The Brigantian shale in Durham that was yielding some nice bits and pieces a few months ago has turned out some quite good trilobites which I'm calling Paladin mucronatus for now. Most of the complete specimens from this locality are enrolled (12 out of 14 so far). Attachments:
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tqb
Enthusiastic fossilologist
Posts: 111
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Post by tqb on Sept 12, 2011 10:05:33 GMT -5
20mm long Attachments:
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tqb
Enthusiastic fossilologist
Posts: 111
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Post by tqb on Sept 12, 2011 10:06:55 GMT -5
enrolled with genal spines Attachments:
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tqb
Enthusiastic fossilologist
Posts: 111
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Post by tqb on Sept 12, 2011 10:14:04 GMT -5
sorry, that last pic was a bit big. Here's a semi-enrolled one that needs prepping, I think it could eventually be the best specimen: (about 20mm long again) Attachments:
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Post by Joe Botting on Sept 12, 2011 10:30:37 GMT -5
That's an impressive assemblage, Tarquin.  Are there lots of fragments as well, or is it a high proportion of complete specimens? The high frequency of enrollment suggests an event bed - rapid burial. What was the sedimentary sequence and bedding like? Looks like an interesting place. Just trying to remember what you've reported from there before... |
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tqb
Enthusiastic fossilologist
Posts: 111
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Post by tqb on Sept 12, 2011 11:28:44 GMT -5
Thanks, Joe; as far as I can tell (so far, the complete ones are all from detached blocks) they come from one horizon about half a metre above the limestone at the base of the cyclothem.
They're associated with crinoid, shell and bryozoan debris and I agree it looks like a burial event.
The rest of the bottom metre of shale is generally packed with brachiopods, crinoid debris, bryozoans and fairly frequent small orthocones as well as trilobite fragments (and probably the odd complete one). Above that, fossils are scarce and it eventually becomes non-marine below the overlying sandstone.
It's hard to work out detailed stratigraphy as the outcrop is covered with a buildup of weathered fragmented shale - needs digging out.
The stuff I've collected is from the few larger weathered and disintegrating blocks. It doesn't split along bedding planes very well so collecting is not as systematic is you'd like.
Off for another look in a few days - I'll try to do some proper geology!
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Post by ammocarbsteve on Sept 13, 2011 5:56:12 GMT -5
Tarquin, Pretty impressive selection there. I'm sure I was once told that complete Trilobites from the NE are relatively rare lol. It looks like your lucks in ) |
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Post by gritstone on Sept 13, 2011 16:02:40 GMT -5
14 trilobites your luck must be in.
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