Reasons for a name

In 1854, some geologists called “upper Eocene” part of the Tertiary succession of Belgium, namely the “Loam of Boom”, the “mussel rock” at Sternberg, in northern Germany, and the yellow sands near Cassel, in France. Sediments of this age were not well represented in Charles Lyell’s British study areas, and the English geologist would rather call these strata the “older Miocene.” To solve the problem, Heinrich Ernst von Beyrich defined a new interval on the basis of the Belgian and German marine formations and their fossil molluscs.

It was Jules Pierre Desnoyers who first reported, in 1825, that the Tertiary could be subdivided in two successive intervals, each characterised by a distinct fossil fauna of marine molluscs, and it was Gérard-Paul Deshayes who pointed out, around 1828, that the divisions were instead three. Working in conjunction with Desaheys, with names inspired by Wiliam Whewell, Charles Lyell proposed in 1832 to name Eocene, Miocene and Pliocene those three distinct Tertiary faunas, a numer increased to four considering his proposal to divide the Pliocene into “older” and “newer”. Given this useful antecedent, the same solution was proposed for the Eocene and Miocene: in further advancement of knowledge, Lyell predicted an “older” and a “newer Eocene” shall be one day, together with an “older” and a “newer Miocene”.

Such was the state of the art, in 1833, after the publication of the third volume of the Principles of Geology. In 1839, Lyell introduced the term Pleistocene for fossils and strata of his “Newer Pliocene”. Keeping to Lyell’s gradualistic approach to naming new stratigraphic subdivisions for the Tertiary, Von Beyrich derived the name Oligocene from the Greek words oligos (meaning “Few” or “Scanty”) and kainos (meaning “Recent”): Oligocene shell beds contained more modern (extant) species than their Eocene counterparts, but less than the Miocene formations.

 

Learn more

Bergreen W.A. (1998) The Cenozoic era: Lyellian (chrono)stratigraphy and nomenclatural reform at the millennium. In: Blundell D.j. & Scott A.C. (eds.). Lyell: the past is the key to the present. Geological Society, London. Special Pubblications 143, 111-132.

Beyrich E. (1854). Uber die Stellung der Hessischen Tertiarbildungen. Berichte der Königlichen Preussischen Akademie der Wissenschaften zu Berlin, 640-660.

Boué A. (1831). Critical observations on the ideas of M. Alexander Brongniart, relating to the classification and probable origin of Tertiary deposits. Edinburgh New Philosophical Journal, 12, 159-172; 340-345.

Lyell C. (1833). Principles of geology, being an attempt to explain the former changes of the Earth’s surface, by reference to causes now in operation. London: John Murray. Volume 3.

Rudwick, M. J. S. (2005). Bursting the limits of time. The Reconstruction of geohistory in the age of Revolution. Chicago: University of Chicago Press. 708 pp.

Rudwick, M. J. S. (2008). Worlds before Adam. The Reconstruction of geohistory in the age of Reform. Chicago: University of Chicago Press. 614 pp.

On the web

See “Oligocene” in Wikipedia.