327 The Oligocene of the Southern United States 17 



strikingly intermediate charadler of the fauna of the Magdeburg 

 sands and the Septaria clays. Nevertheless, he refers them both 

 to the lower Miocene. 



Name Oligocene proposed, ^^^4. Continuing his researches, 

 he found these faunal differences so constant that the following 

 year, he referred the beds to an independent period. This he 

 named the Oligocene,* and considered it as coordinate with the 

 Eocene and Miocene periods. 



Magdebnrg sands. The Magdeburg sands, which represent 

 the lower Oligocene beds in Germany, are characflerized by Ostrea 

 ventllabnim, Area appendicn/ata, Pleurotojna Beyrichi and P. sub- 

 eo7ioidea. The sands are most fossiliferous near Neustadt- Magde- 

 burg, Osterweddingen and Westerregln. The lower Oligocene 

 fauna of these and other localities has been studied especially by 

 Philippi,t Beyrich,J Speyer,|| and von Koenen.i^ 



Septaria clays. The Septaria clays of Hanover and Mecklen- 

 burg, which correspond to the Septaria clays of Boom and Mainz, 

 and represent middle Oligocene deposits, sometimes attain a depth 

 of 160 metres. Foraminifera are very characfteristic in these 

 clays. The commonest raoUuscan species are Leda Deshayesi, 



* 3/ouatsbericht der Berliner Akadeniie der ll'issenschaften von Nov. 



i«54- 



t Beitrager zur Kenntniss d. Tertiarversteinerungen d. Nordwestlichen 

 Deutschlands. Cassel in 4°, 85 pp. 4 pi., 1S43; Verzeichniss der in d. Gegend 

 von Magdeburg aufgefundenen Tertiarversteinerungen. Paleontoo;raptuca I, 

 pp. 42-90, pi. 7, fig. loa, 1S47. 



% Die Conchylien der Norddeutschen Tertiargebirges, Berlin, in-8°, 30 pi. 

 Also published in Zeits. d. Dciiisch. f^eol. Gesellsclia/t, V, VI, VIII, 1S53, 

 55- 56. 



II Ueber einige Tertiar-Conchylien von Westeregeln ini Magdeburgischen. 

 Paleonto^^raphica, IX, Zci.'citer Liefer!iii<^, pp. 80-85. 



^ Die Fauna d. Unter-Oligocaenen Tertiarschickten v. Hehnstiidt bei 

 Braunschweig. Berlin, in-i2°, 75 pp., 2 pi. (Extrait dii Jouni. de hr Soc. 

 geol. alle>nande, annee 1S65, p. 459, pi. 15 et 16); Beitrager zur Kenntniss der 

 Mollusken-Fauna d. Norddeutschen Tertiargebirge. Paleontographica part 

 XVI, p. 145, pi. 12 to 14, 1866; Ueber die Unter-Oligociene Tertirirfauna von 

 Aralsee. Marburg, in-8°, 31 pp., 1869. {Bull, de la Soc. imp. des Nadtral- 

 istes de Moscou. n. i. ) 



See also Bottger, Osc, Beitrag zur palaontologischen u. geologischen 

 Kenntniss d. Tertiarformation in Hessen. Offenbach, 1869. 



