Fossils at Lyme Regis
On this page: When taking photos for my landslips page, I also photographed some common fossils. I thought these might be interesting for people who will be visiting Lyme. These photos were all taken at Monmouth Beach to the west of the resort, but you can find lots to the east too, at Black Ven, for example.
For the casual palæontologist, Monmouth Beach is a good place to start, since it has lots of large and distinct fossils to see, and there's no need to take a hammer and chisel. But you must be careful not to ferret in the cliff face, unless you want to risk death by a thousand rocks. There are plenty of things to see in the fallen rocks on the beach!
To get to Monmouth Beach: either park at Holmbush or the Cobb (the latter is closer but 60p an hour to park; Holmbush is long-stay but a steep walk uphill at the end of the day). With the sea on your left, walk along past the beach huts and chalets, and you will arrive in just a few minutes. At low tide, you can walk miles along the coast if you have the stamina, but it's hard work on the rockier stretches, and you cannot safely climb the cliffs if you get cut off. (You can check tide times online - needs free registration.) To get some idea of the coastline here, you can visit the Millennium Map site: this link goes to an aerial view of the eastern end of Monmouth Beach, and you can use the arrows to travel west and south along the Undercliff, or east to the Cobb and Lyme itself.
|Ammonites are one of the most famous fossils at Lyme. They are the shells of extinct relatives of today's Nautilus, a cephalopod (like octopi, squids and cuttlefish). The spiral shells were made up of gas-filled chambers separated by internal walls; the creature lived in the last and largest one. In this example, you are looking at a slice through the spiral, and you can see the sutures: wavy lines where the chamber walls join the outside part. You may find a specimen which shows the ribs on the outside of the shell, but these soon get worn away by the action of the waves. Sutures can be very elaborate (as shown above right), and are a useful guide for experts to identify different species, as each has its own unique "signature".|
|Halfway to Devon Head (where the Devon/Dorset county boundary crosses the beach), there is an exposed pavement full of large ammonites (30-75 cms across), and you can find lots of examples in broken limestone blocks nearer to the Cobb, like the one shown above. Some fossils are full of sparkling white calcite crystals, and others are made of iron pyrites or fool's gold - Black Ven is a good place to find small pyritised ammonites if you are patient. (It's also a good place to find belemnites: the internal shells of another cephalopod, shaped like elongated bullets.)|
|Fossil wood is quite common. This piece is the biggest I've seen, about 120cms long, and is embedded in a hard limestone nodule. Some of the wood is brownish and fibrous-looking, like this, and other is much more like hard coal.
Nodules can be a good source of whole fossils - they are rounded pale grey stones, often with faint horizontal striations in them. You need a hammer and a bolster chisel to split them open successfully - throwing them down on another rock rarely works and often results in bruised toes! Shale (soft dark grey sheets or blocks) is much easier to break up, and often has lots of fossils in it, but they are not usually so well-preserved or durable.)
|Shells other than ammonites are also common - mostly bivalves like this big clam, which has a shell about 15cms across. You may also find "Devil's toenails" - these are sections through oysterlike shells (Gryphaea) that look like big white toenail clippings in the rocks!|
|This is a close-up of some broken crinoid stems - small star-shaped sections from the stalk of an echinoderm also known as a sea-lily, related to today's starfish and sea-urchins. Mostly they occur in a broken jumble of debris like this, but at Black Ven you can sometimes find more complete examples. The brownish patches are rusty pyrite.|
|Here are some trace fossils - traces left behind by living creatures. Left: burrows seen in plan and section, on the top and side of a limestone block. The lighter rock shows where they were later filled in by different sediments. Although trace fossils are less noticeable, they are probably the easiest thing to find on the beach here, and they come in all shapes and sizes, reflecting the variety of creatures that were living here some 200 million years ago. Above right, the burrows are filled with darker rock, and you can see a clear patch where the right-hand ammonite was lying on the surface long ago.|
I hope these have whetted your appetite for a fossiling trip to Lyme! There are guided walks available with the ex-Warden of the Charmouth Heritage Centre, weekly fossil walks advertised on noticeboards and posters, and you can buy specimens from the several shops in the town if you don't strike lucky. You can find more fossil and cliff photos at these sites: Dr Ian West's field guides, and Graeme Caselton's Jurassic Cliffs page.
P.S. I used to be the editor for this locality at the Open Directory Project (but because it is such a backwater, I keep getting bumped off for not adding enough sites - sigh!): you can see my very own custom-designed Mozzie at this page, although the pages I added have long gone Famous Localities - Lyme Regis.