Search the Community
Showing results for tags 'protochonetes striatellus'.
The thread http://www.thefossilforum.com/index.php?/topic/84678-adams-silurian/ was getting rather enormous, so I have decided to leave that one to deal with the Llandovery and Wenlock and put my specimens from the Late / Upper Silurian here, though I don't have a great deal of material from the Ludlow and Pridoli yet. However, I do still have some jolly nice specimens to show off here. Here are my other collection threads for the Cambrian and Ordovician ; http://www.thefossilforum.com/index.php?/topic/78887-adams-cambrian/&tab=comments#comment-832018 and : http://www.thefossilforum.com/index.php?/topic/78974-adams-ordovician/&tab=comments#comment-832912 In the mid 1980's, on the way home from one of my annual visits to the Hay-on-Wye second-hand bookshops, I managed to persuade my girlfriend at the time to take a bit of a detour and stop off at a roadcuttting just outside Aymestrey,, Herefordshire in the Welsh Borderlands. The rock here is the Aymestry (sic) Limestone Formation, part of the Upper Bringewood Beds and is Gorstian, Lower Ludlow in age, so about 426 mya and a little younger than the Much Wenlock Shale Formation. Many species of coral, trilobites and brachiopods found in the formation are the same as those found at Dudley, but the bed is noted for its massive numbers of the brachiopod Kirkidium knighti (was K. knightii),a lovely, large pentamerid. In fact, during my hour or so searching, I found almost nothing but this species, the only exception being a couple of Atrypa reticularis. The problem was that this limestone is thick and seriously hard, even the broken bits are generally huge, but I managed to obtain half a dozen reasonable specimens and about the same number of fragments. Over the years I have traded, given away or sold them, so that now I only have the best one left. Here is Kirkidium knighti : It's a shame the tip of the beak is broken off : I make index cards for all my fossils, this is the one I made for the specimens at the time, back in the mid 1980's : And today's version : There was a minor extinction between the Wenlock and the Ludlow, known as the Mulde event and it is often said to have primarily effected graptolites and conodonts, but it seems to me it had a massive impact on the bryozoan faunas of the time too. Gone are the varied stony stick and mound trepostomes that made up such an integral part of many faunas from the Middle Ordovician through to the Middle Silurian and even cystoporid groups such as the Constellariidae became extinct at this time. Trepostomes and cystoporids did survive until the end of the Triassic, but were never as important again, the bryozoan faunas would start to become dominated by fenestrids in the Devonian, though they reached their peak of diversity and distribution in the Carboniferous. I will look closely at my limited number of rocks, but I don't think I have a single Late Silurian bryozoan. I know our friend @Mainefossils studies the Late Silurian Leighton Formation in microscopic detail, but I can't recall him posting any bryozoans. Are there any, Asher, old chap? Interesting.