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Material name: CE1b
Synonyms: Silex Crétacé supérieur Est - Sénonien (Campanien)
Material (geologic): Campanian (Senonian, Late Cretaceous) flint

Flake of Campanian CE1b flint
Foto: Jehanne Féblot-Augustins, 2005.

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Material description

  Macroscopically, this type, which occurs only at En Lachat, differs from CE1a mainly in terms of colour: it is a darker grey N4 to N5, a feature resulting from impregnation by organic matter.
Structure: No particular structure.
Texture: Mudstone/wackestone.
Matrix: Depending on area, either colourless and subtranslucent, or dark grey.
Grains: 10 to 12.5 %, whitish skeletal grains, subangular with high sphericity (200 to 300 µ), rare clasts (500 to 1000 µ).
Grain composition: Numerous planktonic foraminifera (biserial Heterohelicidae and small globose forms), several discrete punctated spheres of 250 µ, numerous monaxon and triaxon sponge spicules, occasionally thick-walled, sea urchin radioles, echinoderm fragments.
Further information: Click here for the original French description (opens in a new window), or here for more information on the attributes used in the description (use your browser's "BACK"-button to return here).
Citing: Information on citing this page can be found here.

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Villes-En Lachat
Locality: Villes / En Lachat, France, Ain department
Synonyms: Sampling site Bugey 49 after Féblot-Augustins
Geographical description: The source is located in some fields, under a kilometre away in a northwesterly direction from the hamlet/village of Villes, some eight kilometres SW of Bellegarde-sur-Valserine.
Geographical co-ordinates: east/x 866,3
north/y 2127,5
(Lambert zone II, NTF)

This corresponds roughly with
Lat. 46° 05' 43" N
Long. 005° 46' 53" E

Co-ordinate precision: The coordinates given were taken from a large-scale map, and are within approx. 50 metres of the actual spot.
The latitude/longitude coordinates are a direct transformation of these data on WGS84 and are accurate to the same level; the 1-second precision is given to prevent any rounding-errors.

The location can be found on the 1:25 000 topographical map sheet 3329 W of the French Institut Géographique National.

Geology: According to the geological map, the substrate belongs to the Early to Middle Miocene (without distinction between Burdigalian and Helvetian), unit m1b-2a.

Map of all sampled localities of Late Cretaceous flint in the Bugey (PDF, 54 KB, opens in new window).

Type of source: Secondary. Redeposited Campanian flint from Miocene sediments.
Other types of flint: The flint here constitutes quite a mixed lot, with predominantly Late Cretaceous material like CE1a, CE1c, CE2, CE3, CE4a, CE4b, and CE5, but also Hauterivian (Early Cretaceous) material of the Ht3-type.
  Nodule of senonian flint with neo-cortex
Foto: Jehanne Féblot-Augustins, 2005


Last modified on:
November 15, 2005
Contents primarily by:
Jehanne Féblot-Augustins
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