TIIK cUKTACKors SYSTEM ~>\~> 



Turrilites costatus, Pecten usper, /'. ilulliennei, and Holaster sub- 

 //o6osi/.--. Most of these also range into No. 3, but the whitish chalk 

 above lias few fossils. 



Turonian. The naim- ot tin- >t;i!,'f i.- taken from Touraiiir, 

 where it is divisible into two sub-stages called (1) the Ligerian ami 

 (2) the Angouniian. 



(Calcareous sands aud sandy limestones with Callianassa, 

 AngOtU&iUM Ostrea columbu, and Acanthoceras DevericK, 30 feet. 

 \ Yellow sandy chalk with Acanthoceras deverioides. 

 -Micaceous chalk with I'rionotropis Woolgari, Pachydiscus 

 I pcramplus, and Mammites Revellieri (=Rochbrunei), 60 to 

 Ligerian - 100 feet. 



I Marly chalk with lihynch, Cuvieri, Inocerumuslabiatus, and 

 Galerites subrotundus, 30 feet. 



Traced northward into Normandy these beds pass into pure 

 chalk, and near Rouen the facies is the same as in England with a 

 thickness of about 280 feet. At the base is hard nodular chalk 

 like our Melbourn rock, succeeded by chalk with Mammites 

 nodosoides, Prionotropis Woolgari, and Galerites subrotundus, and 

 this by soft chalk with Terebratulina lata, the higher parts of 

 which contain Holaster planus and Micraster Leskei. 



Senonian. For this stage I retain d'Orbigny's original name 

 instead of the awkward one of Emscherian which has been adopted 

 by de Lapparent or the Corbie'rian of de Grossouvre. The original 

 name should not be dropped, and should be specially applied to 

 that portion of the Chalk which is typically developed round the 

 town of Sens and in the country of the ancient Senones. This 

 comprises the Micraster zones, i.e. those of M, dedpiem (or M. 

 cortestudinarium), M. coranguinum, and of Marsupites (or Micraster 

 turonensis). 



In the Departments of the Yonne, Aube, and Marne, this stage 

 consists entirely of white chalk, in which Hints are often but not 

 universally numerous, and it has a thickness of from 400 to 500 

 feet. Northward in the Aisne and in Picardie it passes into grey 

 and dolomitic chalks with a less thickness, and on the western side 

 of the Paris basin it is represented by sand}" marls, hard limestones, 

 and tine siliceous deposits (" tuffeaux "), the full thickness of which 

 at Villedieu and Saumur is little more than 100 feet. According 

 to M. de Grossouvre the "craie de Villedieu," containing Spondylns 

 truncatus, Micraster turoneiisis, with species of Mortoniceras and 

 Peroniceras, is the equivalent of the Marsupites zone. 



Campanian. This stage is typically developed in the district 

 of Champagne, whence it takes its name, and where it has been 

 divided into four local /ones. It comprises the broader zones of 

 Actinocumax qiiadratus and Belemnitella mucronata, which have a 



