Les diverses interpretations du terme de "Bartonien"

Abstract The various interpretations of the term "Bartonian." Concludes that the term Bartonian should be extended to include all formations from the Lutetian to the Oligocene. Three major subdivisions on the basis of distinct paleontologic zones are recognized: a lower zone--Sables moyens of the Paris basin, Upper Bracklesham beds of the London basin, and Ledian sands of Belgium; a middle zone--Cresnes sands (Paris basin), Barton clay (London basin), Wemmel sands (Belgium); and an upper zone--Pholadomya-bearing marls and gypsum beds (Paris basin), and Long Mead End Sands and Lower Headon beds (London basin). The upper zone is apparently not present in Belgium.