IN THE ANGLO-PARIS BASIN 113 



(1879 : I S8° ; 38-42). Moreover, the time span represented by Beds II to VII at 

 Folkestone are represented in the Alpine area of France and adjoining Switzerland by 

 very condensed deposits in which many horizons are not represented at all. At that 

 time the only description of any detail of the section near Wissant was a poor one by 

 Barrois (1879 ; 27-28) an abridged version of which was given by Jukes-Browne 

 (1900 ; 378-381). Although Barrois had been unable to recognise exactly at Wissant 

 the equivalents of the beds numbered by Price at Folkestone, Price stated definitely 

 (1879 : 1880 ; 34) that they held good at Wissant. So, according to Price, the 

 numbered sequence at Folkestone could be correlated not only with the Aube but 

 also with Wissant. The gravity of this error can be judged from the stratigraphical 

 account of the French sections given above (p. 80) where it is apparent that a major 

 part of the Middle Albian sequence in the Aube is not represented at Wissant and 

 vice versa. Although Jukes-Browne agreed with Barrois that the exact equivalents 

 of the Beds at Folkestone could not be recognised at Wissant, he perpetuates Price & 

 Delatour's erroneous correlation between Folkestone and the Aube (1900 ; 388-9). 

 There is no doubt that this strongly influenced subsequent work on both sides of the 

 Channel, and this is the reason why French geologists of that period considered that 

 the beds at Folkestone included by Jukes-Browne in his Zone of Ammonites lautus 

 were of the same age as part of the clays in the Aube included by them correctly in 

 the interruptus (dentatus) zone. This led to the time spans, which I now label 

 mammillatum, loricatus and lautus Zones, being not recognised at all in Kilian or 

 Jacob's zonal schemes. The historical background to the zonation of the Middle 

 Albian only will now be considered below. That of the Lower Albian has been dis- 

 cussed by Casey (1961a ; 492-499) and the Upper Albian will be discussed elsewhere. 



In Germany the term ' Gault ' included clays of Aptian as well as Albian age (see 

 for example Kilian 1907-13). It had been divided into lower, middle and upper 

 Gault within the first half of the 19th Century and the question of nomenclatorial 

 priorities has been discussed by Spath (1942 ; 670-671). Stolley (1908 ; 246-7) 

 recognised in the 'Oberen Gault ' of north Germany the zones already well established 

 in France. The ' Zone des Hoplites interruptus ' No. 6 is represented by the 

 Minimus Tone and is followed above by the ' Zone der Schloenbachia inflata und 

 Puzosia planulata ' No. 7 to include the Flammenmergel. Jacob's scheme con- 

 tinued to be used in France (e.g. Tomitch 1918, Ciry 1927, Houdard 1940). 



Spath's work on the classification of the Albian commenced with the following 

 arrangement (1921a, 32). 



Gault Up. & Mid. Albian Zones 7 & 6 of Stolley (1908) 



Mammillatus Bed Lower Albian ,, 5 ,, ,, (1908) 



Later in the same year, Spath amplified this classification (1921b ; 311). 



Upper Albian Hor. IX-XIII (Folkestone) Hor. 7 (Stolley) 



(Upper Gault) VI (Jacob) 



Middle Albian f Hor. I-VIII (Folkestone) Hor. 6 (Stolley) 



(Lower Gault) V (Jacob) 

 mammillatum bed 



The mammillatum Zone is, therefore, now included in the Middle Albian. In 1922 



H 



