Lyme Regis, England


On August 1st, 2016; I explored the Lyme Regis region in England.

Lyme Regis area map in England

     This area is a paleontology hot spot, and provides a complete record of every stage of the Jurassic. The fossils of new species are still being found there today.

Geological formations near Lyme Regis

      Lyme Regis is located on the Dorset coast, and represents a significant part of the Jurassic Coast – World Heritage Site. The rocks date predominantly from the Early Jurassic epoch, approximately 199-189 million years ago, during which time a warm sea spread across much of the UK. The famous coastline has yielded a range of spectacular fossils, including: giant marine reptiles, intricate crinoids, ammonites and even dinosaur remains. The volume and quality of finds over the past two centuries in particular, have made Lyme Regis one of the most famous fossil locations in the world.

Looking east down the Jurassic coast, I’m standing just off of the Sea wall east of Lyme Regis.

     The cliffs and foreshore between Lyme Regis and Charmouth represent three stages within the Early Jurassic.  During this time a shallow epicontinental sea (less than 100m deep), was present across much of Europe, including most of England, Wales and Ireland, and laid down alternating layers of clay and limestone. At that time, Lyme Regis (as it’s now known), lay closer to the equator, roughly at the latitude North Africa is today. Overlying the Jurassic sediments are younger Cretaceous deposits, comprising the Gault and the golden coloured Upper Greensand (green when freshly split) – deposited around 106-102 million years ago.  There are two important Jurassic formations present in the cliffs beneath Black Ven -the Blue Lias Formation and Charmouth Mudstone Formation, the latter of which is subdivided into a number of sections: Shales-with-Beef, Black Ven Marls, Belemnite Marls and an isolated exposure of the Green Ammonite Mudstone Member.

Geological Cross section of Lyme Regis area
Looking east down the Jurassic coast. Image taken just off of the Sea wall east of Lyme Regis.

     Lyme Regis was thrust into the limelight in 1811, when a number of significant marine reptile remains were discovered by local fossil collectors Mary Anning and her brother Joseph Anning. Among their finds include the first recognised complete ichthyosaur skeleton, the skull of which was found by Joseph, and the rest of the skeleton by Mary soon after.

An image of Mary Anning found at the Museum in Lyme Regis, England

    

     Fossils can be found throughout the Jurassic and Cretaceous exposures at Lyme Regis, however it’s the Jurassic rocks in particular that attract fossil hunters to Lyme Regis.  Life was abundant during the Jurassic period, giant marine reptiles inhabited the seas.  

The image of an ichthyosaur skeleton found at the Lyme Regis museum.  The large eye of an ichthyosaur was surrounded by a doughnut-shaped bone called the sclerotic ring. Large eyes enabled ichthyosaurs to see well in dim ocean depths.

     In addition to her discoveries of at least three ichthyosaur skeletons, Mary Anning found fossils of two plesiosaurs and a pterodactyl, as well as numerous fish, ammonites (spiral-shelled mollusks that are ancient relatives of the chambered nautilus), brittle stars, and other marine animals, including many belemnites. Like squid, belemnites had ink sacs. One of the belemnites she found was complete with its fossil ink!

 Image taken of a Plesiosaur skeleton, 203 – 194 million years old

     To the west of Lyme Regis the cliffs expose horizontal layers of limestone and shales belonging to the Blue Lias Formation. At low-tide the sea weathered foreshore, known as Monmouth Beach, is exposed and contains abundant ammonites, some of which are approaching a metre in diameter!

An abundance of Ammonites found just west of Lyme Regis

     This incredible stretch, (just west of Lyme Regis),  of foreshore accommodates dozens, perhaps even hundreds of large ammonites among the boulders and in situ on exposed bedrock. These particular ammonites can’t be collected, but their size and abundance makes them worth seeing all the same.

Image found at: https://www.southampton.ac.uk/~imw/Fleet-Lagoon.htm

     Just down the coast of Lyme Regis, (east), is Chesil Beach. Chesil Beach is a shingle barrier ridge, with sheltered lagoons behind, stretching 30 km from Bridport Harbor to Chesil Bay in the Isle of Portland.

Looking south-east at Chesil Beach, England

     At the Portland end, the pebbles are the size of hens’ eggs, yet 24km away at West Bay, the pebbles are the size of peas.

Looking north on Chesil Beach, England

     In between, the pebbles decrease steadily in size so perfectly that fisherman beaching at night can tell where they have landed just by the grade of stones underfoot. 98.5 percent of the rocks are chert pebbles, while the remainder is quartzite, quartz, granite, porphyry, metamorphics and limestones.

Looking south-east along Chesil Beach 

     Nearby, north of Chesil Beach, I visited that evening, the largest and best preserved of England’s hillside figures carved into the green turf near the village of Cerne Abbas.

The Cerne Giant, England in August 2016

     He is uncompromisingly pagan; 60 m tall, brazenly naked with an erect phallus, his ribs and nipples delineated. In his raised hand he wields a knobbed club 40 m long; his left arm is outstretched and he may once have held an object in his left hand.

A close up image of the Cerne Giants knuckles holding onto a club, (It shows the white Kimmeridge Clay underneath the field grass)

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