A. J. Jukes- Broicne — Tico Stages in Upper Chalk. 371 



de Mercey ; further, that he proposed two new stage-names when he 

 might have adopted those used by de Grossouvre. On the other 

 hand, it seems to me that de Mercey was right in principle and that 

 he was quite justified in saying — "L'equite scientifique exige que les 

 denominations des etages de d'Orbigny subsistent dans le nomenclature, 

 quels que soient les changements apportes dans la delimitation des 

 etages, ou bien les demembrements operes a leur depens." 



I am therefore strongly of opinion that the name Senonian should 

 be used for one of these stages, and the only question is to which of 

 them should it be applied. The name is taken from the tribe of the 

 Senones who inhabited the country round Sens, and so far as this 

 typical area is concerned it might be used equally well for either 

 division, since the beds of the Lower Senonian crop out to the south- 

 east of Sens and those of the Upper Senonian to the north-west. 



We need therefore only consider to which stage the name can be 

 most usefully and conveniently applied. Now de Grossouvre has 

 shown that the ' Maestrichtien ' is not a sub-stage, but only a part 

 of the zone of Pachycliscus neulergicus, which is elsewliere included 

 in the Campanian ; in the same way its equivalent in Aquitaine 

 (the Dordonien) is shown to be merely part of the Campanian.' 

 Consequently he adopts the name Campanian (derived from the 

 ' champagne ' of the Charentes) to denominate the stage for which 

 de Lapparent introduces the new name of Aturian. Campanian has 

 the priority, and is now generally recognized by French geologists 

 as a good name for this division of the Tipper Chalk. There is, 

 therefore, no need for Aturian, which should be dropped as 

 a synonj'm. 



On the other hand, all the names proposed for the ' Senonien 

 Inferieur ' are open to objection. The application of Santonian to 

 the whole stage is untenable, because the real and original Santonian 

 was only a part of it, and Coquand was right in so regarding it. The 

 name Corhierien has not found favour in France because it is taken 

 from a locality, Corbieres in the Pyrenees, where the beds differ from 

 those of the Anglo-Parisian Basin, both in their fauna and their 

 lithological characters. ^ EmscMrim' is open to the same objection, 

 the Emscher marls being a local faeies and their fauna a poor one, 

 especially in Echinoderms, so that they do not form a suitable 

 exemplar or type for reference. 



These considerations make it clear that if the name Senonian is to 

 be used at all it should be applied to the lower part of d'Orbigny's 

 division, that of Campanian being adopted for the higher one. 

 Further, there is not the slightest occasion for the use of sub-stages ; 

 a primary division of the series into stages and a subdivision of these 

 stages into zones is all that is necessary, any kind of intermediate 

 term is both cumbersome and useless. 



In its complete development the Chalk of l^orthern Europe appears 

 to be divisible into five stages, though the Danian is of smaller 



^ In both districts, however, it forms the highest portion of his zone of 

 P. neuhergicus, and is characterized by the presence of Splienodiscits 

 Ubaglisi and a special set of Echinoderms, so that it seems to be separable 

 as a distinct zone. 



