Nicky Mansell reveals a trek around the north-west corner of the Island, which reveals how climate change has altered our landscape over millions of years
THIS walk explores the deep history of the north-west corner of Jersey from a time when we were a deltaic environment, going through millions of years of volcanic activity to ice ages and a time when prehistoric people populated the land. It starts on the beach and then takes you up on to the headlands above the Pinnacle and can be extended to take in Grosnez Castle and the bunkers of the Occupation. It tells the story of climate change and man’s impact on the land.
Park at the car park where the Milano Bars once stood on Verte Rue. Start the walk by going down the steps in the granite wall at the southern end of the car park. Head along the beach with the wall to the left.
If you look down in this area you are likely to find remnants of an old forest which looks like peat beds. At times it may be completely covered by sand but there are usually some sections visible among the rocks. Try not to walk across the beds and never take anything as they are a protected site. This is the start of our climate-change story.
Sea levels around the world are affected by the warming and cooling of the atmosphere. This has been happening over hundreds of thousands of years due to cycles relating to the sun’s orbit, the earth’s tilt and solar activity.
There have been periods of extreme cold (ice ages) and warmer ‘interglacial’ periods. The forest here is a relic from over 5000 years ago when sea levels around the Island were lower and the climate was cooler. This would have been when neolithic people were creating the megalithic sites like La Hougue Bie, Faldouet and Grantez. This intertidal zone would have been a coastal plain with alder and birch forest.
Now look around you. From this spot you can also see evidence of much higher sea levels. Look inland around the back of the bay. The old weathered cliff line was created during much warmer periods when sea levels were higher. The flatter land towards the beach could be called a raised beach but is also an area of blown sand.
The story of higher sea levels is further complicated by the fact that the land itself changes due to tectonic activity and adjustment after ice ages so, when the sea was lapping the cliffs around the back of the bay, conditions may not have been much warmer than today but the land has risen so the sea no longer reaches it. Without the sea wall along the bay, the sea could encroach further in land and lap again at the bottom of these ‘fossil cliffs’.
Now walk north along the beach towards Faulkeners Fisheries.
The skyline here is also evidence of different sea levels. La Grande L’Etaquerel to the right of the road is an old stack; the sea would once have surrounded the rocky hill and also the promontory where the bunker and fisheries stand.
Follow the road around towards Le Pulec and go down the slipway.
At certain times of the year you will understand why this area is known locally as Stinky Bay. This was a very popular place for collecting vraic (seaweed) by the local farmers. In 1726 the body of a 77-foot whale was found stranded on the beach. This was claimed by the Seigneur of Vinchelez de Bas and two bones from this beast can still be seen behind one of the gates of the manor.
Walk down the slip until you can see the bay.
You are standing on a geological boundary between the shales of St Ouen’s Bay and the granite of the headland. The shales were laid down in submarine deltaic conditions 600-590 million years ago (MA), and may have been similar to the Mississippi delta today.
They are the grey rocks you can see across the bay and also to the right on Le Petit Etacqueral. You can see how the flat beds of rock have been tilted by earth movements. The granite was intruded over 100 million years later, in about 465-426 MA.
Granite is an intrusive volcanic rock. This means it was formed underground and cooled slowly giving us the lovely pink colour with crystals of quartz, feldspar and mica. It is possible to see where the granite has been squeezed into gaps in the shales in places. There is also a mineral vein running down the bay.
Before leaving the beach, look behind you at the unconsolidated material making the cliff at the back of the bay. This is periglacial head material created when temperatures were much lower and freeze thaw was happening on the cliffs around. Angular blocks would have fallen into the ravines combined with other material sludging down into the valley.
Imagine what would happen if the wall at the bottom was removed. The sea would eventually erode through and Le Grand Etacquerel would become a stack again.
Now walk back up the slip and look to your left.
Here you will see a gulley filled with deposits. This is an interesting spot as it has a mixture of rounded pebbles indicating that it was once beach material showing a previous higher sea level and also angular unsorted periglacial head. If you want to find out more about Le Pulec look on the geology trail website at jerseygeologytrail.net.
Now walk back onto the road and take the footpath to the left, which will take you on to the headland.
The path is steep but the views from the top are well worth stopping to see. If you turn and look south, you can see across the sweep of St Ouen’s Bay towards Corbiàre. The bay is formed in the softer shales and the north-west and south-west corners of the Island are both more resistant granite.
Also from the top you can look down to Le Pulec and L’Etacq where you can see the geological junction and the former stacks of Le Grand Etacqueral and Le Petit Etacquerel. If the tide is low, you will see the reef dissected by straight gullies which are formed along fault lines created from earthquake activity when the Island was on a tectonic boundary.
Keep walking along the footpath closest to the cliff. Once you pass the bunkers on the right, you will get to a point where you can see directly down to Le Pinacle.
This is one of the most important prehistoric sites in the Island. There is evidence of occupation on the site from over 4000 years BC through to Roman times. If you look carefully at the land bridge between the cliff and Le Pinacle, you can see a number of large stones which are part of Neolithic and Copper Age walls.
You can also see the remains of the small Gallo Roman temple. On the cliff to the south, you may be able to spot a horizontal line of a dark grey rock about a third of the way up the cliff. This is a dolerite intrusion. The rock from here was used in the stone axe factory which was thought to be at this site in Neolithic times. It is likely that the people lived on the coastal plain and their remains are lost to the sea.
Now continue north across the boardwalk over the Canal Du Squez.
This is an important marshy area and home to the agile frog. Continue close to the cliffs. The vegetation in this area is a mixture of heather and gorse and bird watchers may see Dartford Warblers. You may also be lucky enough to see choughs from the Birds on the Edge project which now roam free in this area.
If you look back once you have crossed the steam and are on the next headland, you will see the true majesty of Le Pinacle and see why it is considered to be a giant natural menhir. It is, in fact, a fossil stack, again formed during times of different sea levels.
There is a cave which runs under the col and it is not inconceivable that, in the future, this area will be eroded even more and it will become a stack again.
Walk towards the large Second World War observation tower.
This is MP3 (Marine Peilstande), one of the three observation towers built. Nine were planned but this one was the last to be built.
From here, head north towards the castle. There are two paths. Take the one which descends slightly and goes along closer to the sea.
You will go along past a very large perched boulder which from certain points looks like a man’s head.
It is worth going into the castle. Grosnez Castle was built in the 14th century at the beginning of the 100-years war when Jersey and France were constantly in conflict. It acted as a refuge for local farmers but suffered from a lack of fresh water so would never have done well in a siege.
By the 16th century, it was a ruin but it is still worth exploring and the arch makes a classic shot for Instagram. You should also walk down the steps to the small lighthouse as the views to the north and along towards Plémont are breathtaking. On windy days, you may see gannets flying and diving out to sea and, on incoming tides, I have seen dolphins swimming past heading to the reefs off L’Etacq to feed.
From the castle, head along the cliff path to Plemont for about 300m.
Under the cliffs is La Cotte a la Chèvre which is a raised sea cave once used in Palaeolithic times – probably as a short-term shelter unlike the better known La Cotte de St Brelade which was a more permanent home. Don’t attempt to climb down to the cave unless you are with someone who knows it well.
Before taking the small path to the right, spend a moment or two looking towards Plémont and thank the National Trust and States of Jersey for saving this part of the coastline from inappropriate development.
Turn right along the first small path which goes across more heathland and eventually reaches the road back to the castle. Go straight across the road and take the path to the race course. Keeping the white fence to your left, walk back towards the cliffs.
There are a number of small paths in this area which can be taken back towards Le Pinnacle. They are sometimes closed off as they are an important area for the agile frog and toads. If you look down along these paths, you often find small flints which are from the Mesolithic era around 9000 years ago when this was a flint-knapping area for the hunters in the Island.
Once you join the main cliff path, follow it south passing the bunkers and guns of Battery Moltke and descend down to L’Etacq the same way as you came up.
This walk is about four and a half miles and will take about two and a half hours. It is dramatic at all times of the year but my favourite is when the thrift and gorse is out in the late spring.