24 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



as subdivisions of the Paleocene, or within the basal part of the Lower Eocene. 

 Moreover, they tried to introduce these stage names to the type Paleocene, but the 

 relationship between one stage and the other was not clearly understood, and was 

 arbitrarily interpreted by the individuals concerned. Thus, while the Paleocene in the 

 Paris Basin was regarded as including the Thanetian and Sparnacian ; the Montian, 

 Thanetian and Sparnacian ; the Montian and Thanetian ; or the Thanetian alone, 

 it was taken to include the Montain and Landenian in southern Belgium ; the 

 Montian, Heersian (with or without the Infra-Heersian) and Landenian in north- 

 eastern Belgium and in Holland ; the Thanetian, with or without the Woolwich and 

 Reading Beds in England ; the Seelandian, Thanetian and Landenian in Sweden and 

 Denmark, and any further combination of these, plus or minus the Danian. More- 

 over, because of the confusion about the true chronological relationship between the 

 Danian and the Montian, Sigal (1949), followed by most Mediterranean geologists, 

 introduced the Dano-Montian as a new term to cover the early Paleocene period. 



However, in his study of the basal Tertiary in the Franco-Belgian Basin, Feugueur 

 (1955, 1962, 1963) included the Paleocene within the Lower Eocene and equated the 

 Cuisian with the Upper Ypresian, the Sparnacian with the Lower Ypresian, and the 

 Thanetian of the Paris Basin with the Landenian of Belgium, although he pointed out 

 the fact that the Lower Landenian (=Heersian) is missing in the Paris Basin. 

 Feugueur followed Leriche (1903) who had previously recognized in the Landenian 

 a marine lower division and a continental upper one, and divided the marine Lower 

 Landenian, on the basis of its shallow water molluscs, into three zones, from the 

 base upwards: the Arctica morrisi Zone, the Pholadomya oblitterata Zone and the 

 Arctica Scutellaria Zone. However, Feugueur considered the latter zone to be of 

 lagoonal, rather than of marine origin and attached it to the overlying Upper Land- 

 enian, which he regarded as comprising the lagoonal Arctica Scutellaria Zone at its 

 base and the continental Physa gigantea Zone on top. On the other hand, while 

 Feugueur equated the so-called " Thanetian of the Paris Basin " with the Landenian 

 of Belgium, and noted that the basal Landenian (= Heersian = A rctica morrisi Zone) 

 is missing in the Paris Basin, Arctica morrisi was found to mark the top of the 

 Thanetian in England. In spite of this fact, the so-called Thanetian in the Paris 

 Basin has always been equated with the Thanetian of England, which is apparently 

 much older. Thus, despite the value of Feugueur's correlation in the Anglo-Franco- 

 Belgian basin, several problems in the same basin were left unexplained. The 

 relationship between the Thanetian of England and the Thanetian of the Paris 

 Basin ; the Thanetian of England and the Landenian of Belgium ; the Thanetian, 

 the Landenian and the Montian ; the Montian and the Danian ; the Danian and the 

 Heersian ; and the Heersian and the Montian are still not clear. Moreover, the 

 relationships of the other type stages of the Paleocene outside the " Anglo-Franco- 

 Belgian Basin " to each other and to those in the basin were left unsolved. It is not 

 really understood what sort of chronological relationship exists between the Danian 

 and Montian, the Montian and Seelandian, the Montian and Landenian, the Thanetian 

 and Landenian, the Montian, Thanetian, Landenian and the Ilerdian, in their 

 respective type areas. Nevertheless, selected sets of these stage names were 



