|
||||||||||||||||||||||||||||||||||||||||||||||||||||||
Introduction
Llantwit Major borders the Bristol Channel on the south coast of Wales, several miles west of Cardiff and is an excellent place to observe rather than collect large numbers of fossils. The dramatic Jurassic cliffs tower over 100ft above sea level and extend as far as the eye can see in both directions from the beach access point.
(Left) Parking and facilities at Llantwit are very good. (Right) Toilets are available at the beach access point.
Local facilities are very good, with plenty of free parking, a cafe, small shop and toilets too (see photos above). During our recent visit we were greeted by friendly staff and surprisingly low cost food and drinks, good enough to warrant a special mention!
It's worth noting that at high-tide the sea reaches the cliff base and can quickly block your return route; please make a note of the tide times before departing along the beach.
Warning! At high-tide, the sea reaches the cliff base.
The photo above shows much of the beach is isolated by the rising tide. During our recent visit it took less than 30 minutes for incoming tide to cover several meters of the foreshore, due to a combination of shallow beach gradient and highly tidal channel - be warned!
The geology of Llantwit Major
(Left) The cliffs overhang the foreshore precariously. (Right) How long will it be before the lower cliff gives way to the rock above?
The rock exposed at Llantwit Major dates from the Early (Lower) Jurassic, around 200 million years ago; during which time a warm, shallow sea (below 100m) spread over Britain. Marine life during the early Jurassic was rich, with large ammonites and marine reptiles commanding the seas.
Today, the Bristol Channel carves its way through the sequence of rock, exposing dramatic horizontal layers in the cliffs; in fact, travel to the opposite side of the channel at Quantoxhead (Somerset) and you find a continuation of the strata.
Where to look for fossils?
Fossils can be found in abundance on the foreshore and within the broken boulders that have fallen from the cliffs; however the hard rock makes extraction difficult without heavy duty equipment. The fossils at Llantwit Major are best observed rather than collected, as attempts to remove them is more likely to result in their breakage. During our recent visit, despite having sufficient tools, all of the specimens featured in this page were left on the foreshore or in situ.
(Left) Lu searches for fossils among the pebbles on the foreshore. (Right) A significant rock fall that occurred several years earlier.
When searching among the foreshore boulders, it's possible to find rolled pebbles containing a variety of fossils, in particular crinoid stems (see photo below). Other finds include gastropods, ammonites and bivalves, although these are usually partial or the impression of the fossil.
The greatest number of fossils are found protruding from the wave swept beach platforms, visible at low tide; the expanses of bedrock allow visitors to observe fossils (mostly bivalves) in situ.
A limited number of fossils can also be found within the piles of rock accumulated at the cliff base; special care should be taken to avoid walking directly beneath overhanging cliffs though, as rocks falling from this height could have disastrous consequences!
For more information about the features and processes controlling coastal fossil collecting locations click here.
What fossils might you find?
The fossils at Llantwit Major, represent a time of rich marine life during the Jurassic; common finds include ammonites, bivalves, crinoids, gastropods, wood and marine reptile remains, although the latter was not observed during our recent visit.
(Left) A foreshore boulder containing a mass of Crinoid stems. (Right) A large pebble containing multiple bivalves - Gryphea
(Left) A bivalve protruding from the foreshore. (Right) A long piece of fossilised wood/stick.
(Left) The outer edge of a large ammonite shell. (Right) An impression of an ammonite shell.
(Left) A cross section through the underside of a large gastropod. (Right) A paid of bivalves - Gryphea
(Left) The upper shell of a large bivalve protruding from the foreshore - Plagiostoma giganteum. (Right) A cross-section through a small gastropod shell.
(Left) A large portion of ammonite shell. (Right) A heavily sea weathered bivalve shell on the beach platform.
(Left) A calcified ammonite on the surface of a foreshore boulder. (Right) A group of bivalve shells in situ on the foreshore - Plagiostoma giganteum.
Protecting your finds
It's important to spend some time considering the best way to protect your finds onsite, in transit, on display and in storage. Prior to your visit, consider the equipment and accessories you're likely to need, as these will differ depending on the type of rock, terrain and prevailing weather conditions.
(Left) Fossil wrapped in newspaper, ready for transport. (Right) A small compartment box containing cotton wool is ideal for separating delicate specimens.
When you discover a fossil, examine the surrounding matrix (rock) and consider how best to remove the specimen without breaking it; patience and consideration are key. The aim of extraction is to remove the specimen with some of the matrix attached, as this will provide added protection during transit and future handling; sometimes breaks are unavoidable, but with care you should be able to extract most specimens intact. In the event of breakage, carefully gather all the pieces together, as in most cases repairs can be made at a later time...continued.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||
