The Fossils of North Devon
The Pilton beds.
My local! This page is to show a few examples of the typically found specimens in the area I live.
The Pilton beds are a range of Devonian strata formed from sand stones, mudstones and shales. In places they are rich in fossils, although from relativly few species. The specimens displayed here are from the lower pilton and hence Upper Devonian (late Famennian). The sand and silt stones were formed in relativly shallow water, the shales in considerably deeper water as britain moved northwards through tectonic activity. These shales mark the Devonian/Carboniferous boundary in this area of North Devon.
Excellent sections of the Pilton beds can be seen at Saunton sands, and that area is abundant in the water-worn fossils.
Abundant fossil No.2: Brachiopods
Abundant fossil No.1: Crinoids
Igor! The space ships have landed!!!
The round crater to the bottom right is the highly detailed imprint of a single crinoid ossicle (stem-piece). The echinoid ancestry of these creatures is apparent with it's 5-fold symetry. This specimen is tentatively identified as Cyathocrinus.
UK Fossils Portal - Devonian sites in North Devon:
Location: Croyde
http://www.ukfossils.co.uk/sec049.htm
Croyde and next door Saunton Sands are excellent places to view the range of devonian strata in North Devon. The pebble strips of Saunton Sands are relatively abandant in water-worn crinoid remains, better specimens can be found amongst loose debris from the cliff.
REMEMBER: These cliffs can be dangerous. Always act sensibly and keep safety constantly in mind.
Location: Woolacombe
http://www.ukfossils.co.uk/sec086.htm
Along the coast from Croyde lies the large expanse of Woolacombe sands. Popularwith surfers, it gets a mention here as a site where occasional armoured fish remains can be found alongside the tuff beds.
Location: Fremington
http://www.ukfossils.co.uk/sec084.htm
Fremington offers a mix of devonian and carboniferous deposits at a site which is rarely visited by collectors. Most material consists of the ubiquitous crinoid ossicals.
I would love to recomend the Natural History Museums' guide to 'British Paleozoic Fossils' - But I can't as I don't posess a full copy! If you have any specimens you wish to have help for however, then I have several scanned pages, photo's and notes. Contact me through the E-mail address on the front page.
Star find: Trimerocephalus
Trimerocephalus laevis (synonym Phacops laevis). Upper devonian (late Famennian).
This unusual find is the headshield of the upper devonian trilobite Trimerocephalus. Whilst not a particularly striking creature, this little critter once roamed the deepwater silts scavenging for a tasy snack. It can't have been much of a life, as he was only 4cm long originally. To top that, he was also blind - not that there was much to see deep in the devonian murk (Yup! Even back then we were 'Deepest Darkest Devon'!).
What did he (or she) eat? Presumably there were soft-bodied invertabrates in these devonian silts that have failed to preserve, so worms and other such creatures may have been a tasy snack. Crinoid larva could also be a potential meal, although most echinoid larva are free-swimming. Another possibility is that it grazed on algae or similar plants. If anybody reading this does happen to know (and is not just making guesses for idle conversation!), then feel free to contact me via the front page. Any reasonable (or simply hilarious) suggestions will be posted here.
It's not often you get to discuss trilobite feeding habits is it? The little things in life eh? What fun these fossils are!
(Want to see a modern 'trilobitey' critter that you can keep in your own home? I had a tank of 'triops' when I was eight. Great fun they were! Until the big one ate the rest... http://en.wikipedia.org/wiki/Notostraca)
As this specimen is only a headshield it may represent a moult. I was researching trilobites in general before typing this short piece (anything to avoid revision! (Only joking mum!)), and discovered that this particular species marks the devonian/carboniferous transition. It was also one of the last trilobite species of it's family. Over 60 trilobite families existed in the cambrian period, this had fallen to five by the devonian with only two making it to the permian and end of the paleozoic. So this little bug was fighting the rear-gaurd action for trilobites everywhere. Way to go mate.
