356 ON THE MOVEMENTS OF THE EARTH S CRUST. 



of the calculated curve is therefore filled up by the occurrence of thirty- 

 seven alternations, without a gap in the series of deposits. With arc 

 7' the marine formations of the basin terminate. In Miocene times came 

 the volcanic outbursts in Auvergne. 



These oscillations of the coast-lines were not confined to the Paris- 

 basin. The sequence of deposits in the basin of the Giroude, which 

 seems to have been connected with the Paris-basin only through the 

 Atlantic Ocean, is as follows (according- to Vasseur, Ann. Sci. Geol. vol. 

 XIII, pp. 398 et seq.) : 



The Tertiary formations commence with the Middle Eocene: Num- 

 mulitic sand and coarse limestone, marine. After this, elevation and 

 erosion. Then again followed a depression : clay with Ostrea cucullaris 

 (arcs 14 and 15), and another elevation : lacustrine limestone of Plassac, 

 and simultaneously with this brackish- water limestone of Begadan (16' 

 to 1'). Then a new depression: mariue limestone of St. Estephe and 

 limestones and marls with Anomia girondica (2' to 4'). Elevation and 

 erosion : Mollasse (fresh water) of Fronsadais (6"?). Depression : — Cal- 

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

 stone of I'Agenais, level 1 (between 7' and 8'). This is contempora- 

 neous 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 lime- 

 stone of I'Agenais, level 2 (between 8' and 9'); depression: Faluns de 

 Leognan et Merignac, marine (9'). The so-called Mollasse of Anjou, 

 which is wanting in the basin of the Gironde, is, according to Tour- 

 nouer {Ann. /Sci Geol. I. c. p. 62) younger than 9', but older than the 

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

 cate two oscillations, 10' 11'. Then followed another Miocene oscilla- 

 tion, 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 de- 

 posits. 



We now pass to England. In the Memoirs of the Geological Survey 

 of Great Britain, I8.")6, we have accurate profiles of the Tertiary forma- 

 tions of the Isle of Wight (by Forbes and Bristow). The series of 

 beds, from below upwards, has the following oscillations and alterna- 

 tions* : — 



Plastic Clay (brackish?), four alternations. 



London Clay, marine, at least eleven alternations. 



Lower Bagshot, (in part?) fresh water, seven alternations. 



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



the second marine, and with five alternations. 

 Upper Bagshot, without alternations. 



§ee Postscript to tljis article, post, p, 370. 



