Forward to Early Peoples – Back to Foreword – Back to 1789 and all that!
© Bob Denton 2014

1.1 – The Earth science bit!

The French are particularly blessed with a diverse land that has spectacular mountains, great beaches and unspoilt countryside that seems to go on for ever.

If we discount Russia and Ukraine as being on the edge of Europe, then France is the largest European country in terms of land area at 549,970 sq km for Metropolitan France. It is the 43rd largest country in world terms.

We should not overlook that 16% of French territory that exists outside the hexagon in its overseas departments and territories. But for now let’s concentrate on the geology of the homeland itself.

France has 2,900 kms of land border with eight other countries – Spain 623 km, Belgium 620 km, Switzerland 573 km, Italy 488 km, Germany 451 km, Luxembourg 73 km, Andorra 56.6 km and Monaco with 6 km. It has 3,427 km of coastline along the English Channel, the Bay of Biscay and the Mediterranean Sea. (source: CIA World Fact Book)

Of course Corsica sits off-shore and it has overseas properties: French Guiana in south America; Guadeloupe and Martinique in the Caribbean; Mayotte and Reunion in the Indian Ocean.

In the beginning

The Earth’s land masses were formed by tectonic plates moving across the surface of the young globe, creating in turn a series of supercontinents, then breaking them asunder.

Around 700 million years ago it was the supercontinent Rodinia that had coalesced around the equator and you would be hard pressed to point at that part of it which would later become France.

Some 500 million years ago the land masses moved southward to form the supercontinent Gondwana, at that time clustered around what is today the south pole. The land that would become South Africa was centred at that pole. Parts broke away to form Laurentia (Norh America), Baltica and Siberia. At some subsequent stage Laurentia and Baltica, collided and chipped off a chunk that would become the Iberian peninsula.

By 250 million years ago a new supercontinent was born, Pangaea, it sat on either side of the equator and by now the land masses were beginning to adopt their modern hemispherical locations . Though what would become North America was still very much connected to Eurasia and west Africa.

Eurasia was sat 90-degrees to its current orientation with today’s French west coast/border facing south and running along the equator. At around this time there was also a general cooling that led to the Indian sub-continent breaking away from east Africa and starting its move towards Eurasia where it would later collide so catastrophically and threw up, and is still raising, the Himalaya mountains.

From 200 million years ago until the age of the dinosaurs, several major events occurred to move us towards the maps that we recognise from our atlases today.

The first of these happened as the central Atlantic Ocean was created in the void formed as the Americas moved steadily away from the rest of the supercontinent. The Atlantic expanded and pressed northwards between Ireland and Greenland, as it did this it gradually forced Eurasia to rotate clockwise into its current orientation.

The Hexagon

The French often refer to their home as l’Hexagone, the hexagon, its general shape, with three sides that form coasts and three with land borders. The creation of the French hexagon was a series of tumultuous tectonic plate impacts and super rivers that wrought its shape and its nature across many millions of years.

i – One of the hexagonal land borders of France was formed by an event that started off the shores of Iberia. The Biscay abyssal plain expanded and rotated the Iberian Peninsula anticlockwise so that it slowly adopted its current juxtaposition with Eurasia.

More than 500 million years ago the two landmasses, Iberia and Eurasia collided. As they ‘joined’ the impact created the Pyrenees between them. Stretching for almost 500 kilometres from the Bay of Biscay to the Mediterranean; the Pyrenees are much older than the Alps.

The Pyrenees – their name comes from the mythology of Hercules who, while on his way to Geryon slept with Pyrene, the virginal daughter of his host Bebryx. Vying versions suggest either that Hercules was drunk and raped her, others that, though consensual, she despaired when later becoming pregnant. In both versions she became so devastated that during a period of grief she was killed by wild animal/s. Then either, Hercules found her body and shouted her name to the mountains that as a result took on her name. Or, he actually gathered up rocks to commemorate her and this act was what formed the mountain range.

ii – The second land border – from 380 million to 330 million years a collision between Gondwana and Euramerica had helped to form the supercontinent Pangea, and in doing so threw up mountains along what is called the Variscan Belt. These mountains today can be found to span from north America all the way to the Urals.

This tectonic action also threw up a triangular area (500 kilometres long and 340 kilometres wide at its inverted base) that created the Massif Central. It remained an active volcanic region until a geologically recent 66 million years ago.

Another ‘crimp’ achieved by these events can be seen stretching from Brittany, running below the Paris Basin and reaching as far away as Corsica.

But of most significance for our second land border was the creation of the Ardennes and Vosges which preside over the country’s eastern flank.

iii – The third land-border of the hexagon was formed when Eurasia collided with parts of the African continent and thrust up parts of the seabed of an ancient ocean, Tethys. This had sat between Gondwana and Laurasia some 200 million years ago.

This series of events tended to overwrite some of the Variscan Belt outcomes. Most significantly for France, some 180 million years ago, the Alps were formed to become the south-eastern border of France.

The Alps – are distributed across eight European countries. The range describes an arc for 1,200 kilometres (750 miles). Its height and extent directly impacts upon the climate of Europe. Its name is said to derive from a Celtic expression for any high place. Or from a pre-Indo-European word ‘Alb’ meaning hill. This word is also the root of the name Albania.

The range has some 82 peaks higher than 4,000 metres. The highest is Mont Blanc (4,807 metres, 15,750 feet) which sits astride the French-Italian border. The range is the source of one of France’s major rivers, the Rhône, which rises in the Alps from the run-off of the Rhône Glacier in Switzerland. It then runs for 813 kilometres (505 miles), splitting into two before it reaches the Mediterranean; the delta between the two branches is the Camargue.

iv – The southern coast of the hexagon – Some 5.6 million years ago, the Mediterranean had become disconnected from the oceans and had virtually dried up. At its nadir its residual heavily saline waters had receded to between 1,500 and 2,700 metres below sea level.

Barcelona’s Institute of Earth Sciences suggests that although water had been trickling into the Med for thousands of years, some 5.3 million years ago a traumatic event occurred. It is called the Zanclean flood, when Atlantic waters surged through a 200 km channel at today’s Gibraltar Straits and re-filled the Mediterranean. It is sid to have flowed in at a pace three times that of the current rate of the Amazon.

This impressive flow and volume proved catastrophic for the early life forms that had evolved there. Travelling at an estimated 300 kms/hour it raised the sea’s level at 10m each day; it managed to fill the Mediterranean in just two years. If you have ever watched the slow progress when filling a swimming pool, then you can begin to imagine the forces at work to achieve this remarkable event.

v – The northern coast of the hexagon – 500,000 years ago England was still connected to the continent by low hills situated between the Weald and the Artois in northern France. The rivers Rhine and Thames both contributed to form a glacial lake located near today’s North Sea.

Scientists have examined the deposits in the Bay of Biscay to conclude that La Manche (the English Channel) was formed some 450,000 years ago. The North Sea glacial lake grew to a point that it breached the natural dam formed by the landbridge between the countries. The large volume of water flooded as a super river that ate away at the chalk hills and then scoured out an existing river valley between France and England all the way around to the Bay of Biscay.

Successive ice ages and warm periods continued the process, finally consigning England to its island status at the end of the last ice age, just 9,000 years ago.

vi – The western coast of the hexagon – is formed by the Bay of Biscay itself. This large gulf connecting to the Atlantic ocean is called variously Golfo de Vizcaya or Mar Cantábrico by the Spanish and the Golfe de Gascogne by the French; it has also been called El Mar del los Vascos, the Basque Sea.

It stretches from Brest in France to the Cape of Ortegal in the Galician province of A Coruña, Spain. In English it is named for a province in the Basque Country, Biscay, with its principal city being Bilbao.

No fewer than 29 rivers serve the bay area from France and Spain. It covers 223,000 square kilometres (86,000 square miles) with a maximum depth of over 4,700 metres (15,000 feet).

Its shallow continental shelf seems to focus some of the worst Atlantic storms particularly in the winter. Many approaching depressions get deflected northward towards the UK or are turned south where they subsequently become Mediterranean storms. The balance gets enhanced by the Gulf Stream to cause storms up to hurricane force in the bay area.

Historically it has been the site of many wrecks thus becoming much feared by early sailors. During WWII more than 70 U-boats were sunk by the RAF in the Bay and they retaliated by sinking many allied ships; casualties were more than 15,000; understandable then that Germans called it the ‘Valley of Death’.

In summer the southwestern part of the bay often forms a large triangle of fog; a similar phenomenon happens along the USA’s California coast where it is known as the ‘June Gloom’.

The north-south divide

There is one other ‘border’ worthy of mention that is not geological, but rather more of a political and cultural divide.  This is the 45th parallel north which effectively marks the difference between northern and southern Europe and certainly the divide between northern and southern France. The parallel runs just north of Valence, through Grenoble, across the Massif Central and hits the Bay of Biscay just north of Bordeaux.

This ‘border’ divided the French language. South of it is where the Occitan language was spoken, the Langue d’Oc, the region where the word for yes, Oui, was Oc. Today a number of the dialects of Occitan (Auvergnat, Limousin, Languedocien and Provençal) are identified by UNESCO as endangered.

It is also effectively a delineation between cuisines. Simplistically, north of here butter is the most common cooking material, south of it, olive oil is used. Clearly today this is much fudged by the global village.


Some 33% of the French metropolitan land area is arable.

It is well blessed with rivers, sixty-six of France’s 95 administrative départements (70%) are in fact named after rivers. Of these twenty-four of the rivers are of significance, flowing for more than 300 kilometres.

The natural resources deposited by the formational geological events described above are antimony, arsenic, bauxite, coal, feldspar, fluorspar, gypsum, iron ore, potash, timber, uranium and zinc. 

Of its overseas territories French Guiana has significant resources that include clays, gold deposits, kaolin, niobium, petroleum and tantalum.

Forward to Early Peoples – Back to Foreword – Back to 1789 and all that!
© Bob Denton 2014