Reasons for a name

Born in 1811 (of Swiss origin) near Frankfurt, in Germany, Édouard Desor fled to Paris around 1832 and there started a geological career, coming under the influence of Élie del Beaumont. With Lous Agassiz, Desor had a key role in the study of glacial phenomena, but is also remembered for his stratigraphic studies, particularly based on the paleontology of fossil echinoderms. Starting from his observation in localities such as the Faxe quarry and Stevns Klint, in Denmark, Desor named a new stage inspired by the Latin word Dania, standing for Denmark. He considered the interval as the youngest tract of the Cretaceous System.

After visiting the island of Zealand, in Denmark, on its way to Scandinavia, Desor recognised similarities between the local limestone and the pisolitic strata that he had studied at Laversine, in the Paris Basin. Both overlied the typical Chalk formation, both contained Cidaris forchhammeri, a species distinct from older echinoids of the same genus. In naming the species, Desor recognised the authority of Johan Georg Forchhammer, the Danish mineralogist who first had studied the Faxe limestone.
Pierre Jean Edouard Desor (1811-1882)
Pierre Jean Edouard Desor (1811-1882)
Cidaris? forchhammeri Desor, 1846 was the most common, but not the only typical fossil of the Faxe and Stevns Klint strata. Other species were mentioned by the german geologist during the 16 November 1846 session of the French Geological Society, when he announced the new Danian stage. Diagnostic fossils included new echinoid species of genus Pyrina and Holaster, and the decapod Dromiopsis rugosus (Schlotheim, 1820), common at Vigny in France.
Cidaris? forchhammeri Desor, in L. Agassiz & Desor, 1846
Cidaris? forchhammeri Desor, in L. Agassiz & Desor, 1846
Mr. Desor thinks that we should consider the Faxe limestone, the coralline chalk and the pisolitic strata at Laversine e Vigny as a particular stage of the chalk, the most recent of all, as it was proposed by Mr. Élie del Beaumont; but this should not comprise the the terrains with Nummulites, that he considers as belonging to a more recent epoch. Mr. Desor proposes to call this stage danian terrain, since it is better developped in the islands of Denmark. As it was coinceived by Mr. Graves, this is probably the continuation of the terrain of Maastricht.
The Faxe quarry, in Denmark
The Faxe quarry, in Denmark (Photo by Theis Kofoed Hjorth).
The chalky cliff of Stevns Klint, in the western coast of Zealand
The chalky cliff of Stevns Klint, in the western coast of Zealand. In the foreground the sharp contact between the Danian and the underlying Cretaceous (Photo by René Eriksen).
The Danian was first thought to be the last stage of the Cretaceous, while pisolitic beds of Vigny, in the Paris Basin, were inscribed in 1865 in a new stage named Montian, from Mons, in Belgium, which most geologist interpreted as the lowermost stage of the Tertiary. The equivalence between the two stages and their placing in the Teartiary were finally recognised in 1979 at the Symposium on the Cretaceous-Tertiary boundary held in Copenhagen, priority being given to the “Danian” (see Montenat & Merle, 2018).
Grand carriére de Vigny, Val-d'Oise (France), Danian parastrotype
General view on the Grand carriére de Vigny (Val-d’Oise, France), Danian parastratotype.
References
Agassiz, L. & Desor, E. (1846). Catalogue raisonné des familles, des genres et des espéces de la classe des Echinodermes, précédé d’une introduction sur l’organisation, la classification et le développement progressif des types dans la série des terrains par M. L. Agassiz. Annales de la Societé nat. 3, 305-374.
Desor, P.J.É. (1847). Sur le terrain Danien, nouvel étage de la craie. Bulletin de la Societé Géologique de France 4, 179-181.
Gravesen, P. (2001). Den geologiske udforskning af Fakse Kalkbrud fra midten af 1700-tallet til nu. Geologisk Tidsskrift 2, 1-40.
Jagt, J.W.M. (2000). Late Cretaceous-Early Palaeogene echinoderms and the K/T boundary in the southeast Netherlands and northeast Belgium — Part 4: Echinoids. Scripta Geologica 121, 181-375.
Lauridsen, B.W., Bjerager, M. & Surlyk, F. (2012). The middle Danian Faxe Formation – new lithostratigraphic unit and a rare taphonomic window into the Danian of Denmark. Bulletin of the Geological Society of Denmark 60, 47-60.
Montenat, C. & Merle, D. (coord., 2018). Stratotype Danien. Muséum National d’Histoire Naturelle, Paris, 480 p., Patrimoine Géologique; 9.
Ravn, J.P.J. (1933). Études sur les pélécypodes et gastropodes du Calcaire de Faxe. Det Kongelige Danske Videnskabernes Selskabs Skrifter, naturvidenskabelig og mathematisk Afdeling 9, 1-74. Surlyk, F., Damholt, T. & Bjerager, M. (2006). Stevns Klint, Denmark: Uppermost Maastrichtian chalk, Cretaceous–Tertiary  boundary, and lower Danian bryozoan mound complex.  Bulletin of the Geological Society of Denmark 54, 1-48. Links See Dromiopsis rugosus (Schlotheim, 1820) at Fossil Crabs.