In 1847, the well-known mining engineer Andre Dumont published a drawing of the Eastern wall of the Wallerant quarry. This was a young quarry, located at Ol' Preu and it is today known to us as the location where Ardennes Coticule currently quarries. Nowadays the distance from top to bottom of the quarry is approaching 40m, but back then it was a good 5m. Dumont made a sketch, measured the thickness of the layers and the distances between them.
1. Veine-aux-Poissons: thickness:3 cm /space in between 1-2: 74 cm
2. Petite-Veinette: thickness:0.7 cm à 3 cm /space in between 2-3: 3 cm
3. Filet: thickness: 0.7 cm /space in between 3-4: 9 cm
4. Grosse-Blanche: thickness:6 cm /space in between 4-5: 30 cm
5. Gros-Grès: thickness: 2.6 cm à 7.5 cm /space in between 5-6: 45 cm
6. Dressante: thickness: 2.6-7.4 cm /space in between 6-7: 45 cm
7. Jolie-Veinette: thickness:1.5 cm à 3 cm /space in between 7-8: 30 cm
8. Petite-Blanche: thickness: 0.7-2 cm /space in between 8-9: 30 cm
9. Les deux Grosses-Latneuses: 1.5 cm / 1.5 cm hybrid / 1.5 cm / space in between 9-10 : 150 cm
10. Nouvelle veine: thickness: 7.5 cm
11. La Grise
(12. La Verte)
(13. La Veine aux Clous)
As you can see, the Coticule band is like a gigantic multilayered lasagna, that has been pushed into a series of folds, by the forces of time, pressure and geological activity. You can see, for instance, how layers 10 and 11 are among the "youngest" layers of the quarry, forming the top of the deposit. Part of that top was eroded away eons ago. It isn't hard to imagine how layer 10 at the far left originally curved and connected with 10 at the middle of the drawing. We can see how it dived a few meters deeper, to turn up again and runs out again a bit further to the right. #10 is La Nouvelle Veine, and this explains why we don't see that many of them. The middle bend had already been fully extracted
at this quarrying location, over an age ago. Only the #10 bend at the left runs deeper into the hill. Much deeper. And so do most of the other layers. Some of the layers known to us today, don't even show up in this sketch, because they are located further to the left, notably La Verte, and La Veine aux Clous. It is important to realize that nowadays, the quarry extents more than 3 times wider to the left of the drawing and almost 8 times deeper.
The middle curve of the layers #1 to #3 is completely mined at the current location. Will they meet another bend of it deeper and more to the left? Unlikely, but one never knows. #4, La Grosse Blanche shows up only on accasion when they are excavating at the front of the quarry (the area of our sketch). La Grosse Gres? I have no idea, perhaps it was later renamed La Grosse Jaune?. Where it really starts for Ardennes today, is with La Dressante (#6), next La Veinette (#7, formerly called Jolie-Veinette), La Petite Blanche (#8), Les Latneauses (#9), La Nouvelle Veine (#10), La Grise (#11), La Verte (#12) and La Veine aux Clous (#13). Those last 3 hadn't been extracted yet, when Dumont made his sketch in 1847.
Kind regards,
Bart.