Silurian:
It's time we branched out a bit. Not much, admittedly, but it's a start. The Silurian rocks of Radnorshire and surrounding areas are also highly fossiliferous in places, with a range of shelly and graptolite-dominated faunas. So far, we haven't really gone into the literature much at all, and so most of what we're finding almost certainly have names somewhere; we just don't know what they are. Hence all our labels of "sp. A" etc.
We've decided to focus on one locality at a time for the moment, and have put our initial effort into an early Ludlow site that will be familiar to all who have driven from Llandrindod to Kington - the Gwernarglwydd cuttings that run along the side of the road during all those fabulous hairpins... These rocks are part of the Bailey Hill Formation, and are basically siltstone, sandstone and calcareous sandstone, with the majority of fossils concentrated into winnowed or storm beds. Many fossiliferous levels consist of dense layers of tiny shells and shelly debris, making them difficult to work with, to say the least. But you can start picking out the best preserved specimens if you put some effort in. We haven't put much effort in at all, yet, but we've still got a few groups, as described below. The groups are generally very similar to those of the Ordovician (see the subsections of the main faunal list for an introduction to these groups), and if any new ones appear we'll add them here.
There are also various bryozoans, but these are more difficult to work with... when we next go back to Wales we'll pick up extra slabs and add them to the list. If any of you have specimens from this cutting, then please compare them with our drawings and see if there are any you've got that we haven't. If you've collected the fossils of a particular Silurian place, then please do start putting an inventory together, and we can see about getting you a similar page.
The drawings are very sketchy at the moment - this is purely the stage of trying to put things together and work out what's there, rather than a formal presentation of the fauna. You never know, though... one day we might improve on them...
Echinoderms. These are probably all crinoid columnal ossicles so far.
Brachiopods. There are probably loads of species of these, but the shells are often so broken it's difficult to do much with them.
Scolecodonts. We've got three without really looking for them, so there are probably loads. It's likely that two of them are different elements from the same apparatus, but we're just using 'form taxa' for the moment.
Ostracodes. A few definitely distinct ones already, and probably several more to come. The detail on the best ones is wonderful. Note the difference between female valves and male/juvenile ones.
Molluscs. There's little we can do with these at the moment: one smooth nautiloid and few bivalves. We really need better material, but based on past experience from the Ordovician, the diversity is likely to be a lot higher.
Graptolites. These are often very weakly preserved (so you can hardly even see them in the field), but can be amazingly abundant. There are some interesting ones, as well, and the biozonation is apparently known, so there must be at least a few different species.
Trilobites. Definitely on the rare side, but they are there. The bobbly one may be an encrinurid fragment, but I'm not entirely convinced. Need more pieces.
Bryozoans. We haven't really started on these yet. There are several species, including thin branching ones and massive blobby things, but it'll take a bit of work to sort them out..
