Numismatic Chronicles

…The Paleogene was proposed by CF Naumann (1866) based on the significant differences in the fauna between the Neogene and the Paleogene. This period is called the Nummulite Period in France and other countries because of the large foraminifera nummulite fossils found in this period. The Paleogene is divided into three periods, Paleocene, Eocene, and Oligocene, from oldest to newest. The boundary between the Paleocene and Eocene is considered to be 55 million years ago, and the boundary between the Eocene and Oligocene is considered to be 38 million years ago. …

*Some of the terminology that refers to the Numismatic Chronicles is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…古第三紀は新第三紀との動物群の著しい差異をもとに，C.F.ナウマンによって提唱された(1866)。この時代は大型有孔虫のヌンムライト(貨幣石)の化石が多いため，フランスなどでは貨幣石紀とよぶ。古第三紀は古いほうから，暁新世，始新世，漸新世に三分され，暁新世と始新世の境界は5500万年前，始新世と漸新世の境界は3800万年前とされる。…

※「貨幣石紀」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報