By Ian Donaldson

You can tell you're back in France by the intoxicating aroma of the drains. The short walk from the Eurostar station to the centre of Lille passes a modern office block with a difference. All the plate glass windows have been painted in multicoloured horizontal stripes. The French have a wonderful way with architecture which makes the most ordinary office block look interesting. Sadly, this cheery facade hides Euralille, a rather gloomy and unremarkable shopping mall.

Unremarkable, that is, apart from a unique display of geology which most passers-by don't notice. It's in a hallway at the top of some escalators, and is a long and very slim pyramid made of polished slabs of the rocks under Lille. Starting with the Quarternary and going back to the Precambrian, each slab's size is proportional to the thickness found locally. And a 50 yard long paving of black polished rock, probably diorite, leads from this wafer of a pyramid to end at the base of a tall thick round pillar on which the various geological eras are displayed. A white marble plaque on the pyramid describes the rocks and their formation. So there are 1600 metres of Cambrien - 500 Million d'Années, 955 metres Silurian - 400 MA, and several I didn't recognise - 900 metres of Couvenien, 380 MA, 443 metres of Givetien - 374 MA and 152 metres of Franien, 370MA. The list ends with Famennien, Tournnien, Turoniel, and finally "Sol Actuel Quaternaire, age en cours".

If only British malls could do the same.

This wasn't the only surprise in town. The Grand Place was repaved several years ago when Lille was a City of Culture. It's still the usual mix of pink and white granite, though a lot flatter and smoother than the cobbles of old, and beautifully laid out. Even the zebra crossings are made of white marble cubes. One cobble caught my eye, for it alone was polished. It bore the inscription Granit de Lanhélin. This is as famous in France as Shap is in Britain, and is now used a lot for kitchen worktops. It comes from Brittany, in an area north of Rennes, and south-east of St Malo.

The Museum of Natural History and Geology is a twenty minute walk from the centre towards the university quarter. This is a Victorian wrought iron affair, slim, but over 200 feet long, with a gallery reached by spiral staircases. The Visitor's Guide will give you some idea of

what to expect :-

In the environment of an architecture end 19th century, the museum became impossible to circumvent. As of the entry, mammals, birds regional and exotic, skeletons, insects and arachnids fascinate the visitor. While an immense skeleton of cachelot floats in the airs. In the geological part, where sometimes it is possible to hear the dinosaur shouting, you will discover the history of the ground, ....

Gerald Hoffnung didn't have to make it up.

 The first exhibit is a giant boulder of limestone, without explanation, and likewise there are no tags on the immense polished slabs of granito-gneiss, and of black limestone rich in turret shells.

But adjacent to these are hands-on samples of many common rocks, each pivoting on vertical metal rods. So you can touch the samples, which are labelled. Sadly, though you can rotate them, you can't pick them up and compare their weights as they're firmly anchored to the rods.

There are good explanations of erosion, plate tectonics, volcanoes and earthquakes. A large lump of homogeneous grey-white limestone is labelled "Grès" It looked familiar, but only some days later did I recognise its similarity to Portland Stone. The end of the gallery has a short dark tunnel of a coal mine, presumably a source of local wealth in years gone by, and a display of miners' tools. The ground floor also has a paved area of plate glass, covering the excavation of an almost complete skeleton of a small dinosaur. It's fun to walk over this to the amazement of young children who've been told they shouldn't walk on the glass. The first floor mineral gallery delighted and surprised me, especially the radioactive ores which may no longer be on public view in Britain. So if you want to see Pitchblende, Autonite, and Torbernite this is the place to go. Many minerals were new to me - for example Vivianite, a hydrated iron phosphate from the Ukraine, and Pectolite, a sodium calcium silicate hydroxide from Patterson, USA

The carbonate minerals are nicely arranged, but there is no sample of Ankerite. I did learn however that though calcium carbonate can exist in two crystalline forms, rhombic calcite, and aragonite which looks like straight hexagonal columns, thereafter the series splits into two lines. Those based on the aragonite form are Cerusite, Strontianite, and Witherite, the carbonates of lead, strontium and barium respectively. Their hexagonal forms are due to hexagonal close packing of the metal ions.

The calcite series includes Magnesite (Mg), Otavite (Cd), Rhodochrosite (Mn), Siderite (Fe), Smithonsite (Zn), and Sphaerocobaltite, the cobalt carbonate.

Smithson was the Somerset man who owned the Mendip zinc mines and left his fortune to found the Smithsonian Institution in the newly established United States of America.

Beneath the exhibits are drawers. Surprisingly these don't contain further samples as you would expect, but a single piece of paper giving technical information about the rocks, fossils and minerals. What a waste of good drawers. Dotted around the museum for the education of the public and the irritation of nit-pickers are three or four microscopes which as usual don't work.

So it's an interesting if somewhat unloved display. The entrance fee is modest, and I hope to spend longer there next time. They seem to have forgotten that geology is an important part of their museum which now has the title Musée d' Histoire Naturelle Industriel Commercial et d'Ethnographie Lille

Sources

Horace Sanders has kindly pointed out that Mier's Mineralogy has a good section on carbonates, and clear and extensive details about their crystal structure can be found at www.galleries.com/minerals/carbonat/ Pictures of the granite are at www.hignant-granits.com and of the geology museum at www.mairie-lille.fr/LilleTouristique