Vol. 65.] FOSSIL PLANTS FROM THE KENT COALFIELD. 35 



more recent than the Kadstock Series of Somerset, or more ancient 

 than the lowest beds of the upper zone, containing the ' Charbons 

 gras et flenus ' of the Pas-cle-Calais Coalfield. 1 It may be remarked 

 however that, in 1892, the Upper Transition Series had not yet 

 been marked out as a horizon, distinct from the Middle and Upper 

 Coal-Measures, and that the North Staffordshire Series, which, as 

 Prof. Zeiller pointed out, contains these two species, was then 

 termed ' Upper Coal-Measures,'" though now referred to the Transition 

 Measures. 



Two years later, however, Prof. Zeiller 2 correlated the Dover Beds 

 with the Upper Zone of the Pas-de-Calais Coalfield, since eight of" the 

 eleven species recorded by him from the former occur in the latter. 

 This zone, that is, ' Zone C,' or the ' Charbons gras et flenus,' was also 

 found to be the equivalent of the British Transition Series in the 

 same year. 3 Thus the Dover Series has been shown, indirectly, to 

 belong to the Transition Series. 



From the table given on p. 32 it will be seen that three 

 important species from Dover, among others, occur in both the 

 Waldershare and the Fredville Series. Two of these, Neuroj>teris 

 rarinervis, Bunb. and JV. scheuchzeri, Hoffm., are Upper Coal-Measure 

 plants, while N. tenuifolia (Schloth.) is essentially a Middle Coal- 

 Measure species. Thus such agreement as exists between these 

 floras indicates that all three series belong to the same horizon. 



Comparing the floras of the Waldershare and Fredville Series 

 with those of the Pas de Calais and Nord de France (Valenciennes), 

 the nearest Continental coalfields (see table on p. 36), we find that 

 -the great majority of the species are common to the highest zone in 

 the Pas de Calais. 4 



The only species absent from the French coalfields are Odonto- 

 jjteris lindleyana, Sternb., Pecopteris arborescens (Schloth.), a 

 doubtful record from the Waldershare core, Eremopteris artemi- 

 sicpfolia (Sternb.), Cardiocarpus acutus, L. & H., and Cordaicarpus 

 •corculum (Sternb.). On the other hand, the close agreement of the 

 Kent flora with that of ' Zone C,' or the ' Charbons gras et flenus,' of 

 the Pas-de-Calais Coalfield, 5 leads to the conclusion that the horizon 

 of the Waldershare and Fredville Series is homotaxial with this, the 

 highest, zone in that coalfield. Thus the horizon indicated by a 

 comparison with the floras of other British coalfields is confirmed : 

 for, as Prof. Zeiller 6 has shown, the ' Charbons gras et flenus' of 

 the Pas de Calais are to be regarded as equivalent to the British 

 Transition Measures. This horizon is not represented in the Nord- 

 de-Frauce Coalfield. 



'I ! Looked at broadly, the Kent Coalfield is of especial interest, as 

 adding another link to the chain of coalfields which stretches from 

 Westphalia to the western coast of Wales. There are good grounds 

 rfor the belief that a more or less continuous sheet of Carboniferous 



i Zeiller (92) p. 629. 2 Id. (94 2 ) p. 123- 3 Id. (94 1 ) p. 495. 



* Boulay (76) ; Zeiller (88), (94 1 ). • Zeiller (94i) p. 490. 



■6 Zeiller (94*) p. 495. 



