the Displacement of Shore-lines. 497 



terminate. In Miocene times came the volcanic outbursts in 

 the Auvergne. 



These oscillations of the coast-lines were not confined to 

 the Paris-basin. The sequence of deposits in the basin of the 

 Gironde, which seems to have been connected with the Paris- 

 basin only through the Atlantic Ocean, is as follows (according 

 to Vasseur, Ann. Sci. Ge'ol. vol. xiii. pp. 398 et segq.) : — 



The Tertiary formations commence with the Middle Eocene : 

 Nummulitic sand and coarse limestone, marine. After this, 

 elevation and erosion. Then again followed a depression : 

 clay with Osti'ea cucullaris (arcs 14-15), and another elevation: 

 lacustrine limestone of Plassac, and simultaneously with this 

 brackish-water limestone of Begadan (16-1'). Then a new de- 

 pression: — marine limestone of St. Estephe and limestones and 

 marls with Anomia girondica (2'-4'). Elevation and erosion : — 

 Mollasse (freshwater) of Fronsadais (6' ?). Depression: — Cal- 

 caire a Asteries de Bourg (marine, 7'). Elevation: — lacustrine 

 limestone of l^Agenais, level 1 (between 1' and 8') . This is con- 

 temporaneous with the Calcaire de Beauce of the Paris-basin. 

 In the basin of the Gironde fresh oscillations took place, namely 

 the following, which are Miocene : — Faluns de Bazas, marine, 

 8'; elevation: lacustrine limestone of I'Agenais, level 2 (between 

 8' and 9') ; depression : Faluns de Leognan et Merignac, 

 marine (9'j . The so-called Mollasse of Anjou, which is wanting 

 in the basin of the Gironde, is, according to Tournouer (^Arti. 

 Sci. GeoL I. c. p. ^'1) younger than 9', but older than the 

 Faluns de Salles of the Gironde ; both are marine, and pro- 

 bably indicate two oscillations, 10', 11'. Then followed another 

 Miocene oscillation, which has left its traces in the basin of 

 the Loire, in the marine Faluns of la Dixmerie (arc 12'). 



Thus the Miocene period in France had five oscillations. 

 I have not, however, been able to obtain detailed profiles of 

 all these series of deposits. 



We now pass to England. In the Memoirs of the Geolo- 

 gical Survey of Great Britain, 1856, we have accurate profiles 

 of the Tertiary formations of the Isle of Wight (by Forbes 

 and Bristovv), The series of beds, from below upwards, has 

 the following oscillations and alternations* : — 



Plastic Clay (brackish ?), 4 alternations. 

 London Clay, marine, at least 11 alternations. 

 Lower Bagshot, (in part ?) freshwater, 7 alternations. 

 Middle Bagshot (Bracklesham and Barton), the first fresh- 

 water, the second marine, and with 5 alternations. 

 Upper Bagshot, without alternations. 



* See Postscript, p. 513. 



