Vol. 65.] FOSSIL PLANTS FROM THE KENT COALFIELD. 37 



Wales Coalfields, and the barren coalfield of Devon & Cornwall, 

 all lying to the north or south of this great east-and-west axis, 

 may be regarded as a succession of basins, distinct, at least tectoni- 

 cally, from the Pennine system of coalfields in the Midlands and 

 the North of England. This group is worthy of further study as 

 a whole, from a broad standpoint, and this remark is especially 

 applicable in regard to the fossil flora. At present, our knowledge 

 of the plants of these coalfields is still very imperfect. One de- 

 duction of great interest may, however, be drawn provisionally. 



The fossil flora of these rocks belongs to the lower of the two 

 great continental zones of the Upper Carboniferous, widely 

 known on the Continent as the Westphalian. This term has 

 been in use since 1892, l in a far broader sense than that recently 

 proposed by Dr. Kidston, 2 who would adopt it as a name for the 

 palaeobotanical zone generally known in this country as the Middle 

 Coal-Measures — a fact which militates against the acceptance of 

 his new scheme of zonal nomenclature. The British Middle Coal- 

 Measures is only one horizon in the Westphalian, and further it is 

 a local horizon, which is not as a rule to be traced over wide areas ; 

 whereas what may be termed a continental zone is found to 

 be constant over continents or hemispheres. 



Though the higher continental zone, the Stephanian, is not 

 represented in the Mendip-Artois series of basins, we have, 

 however, in England and Wales, what may perhaps be a transition 

 between the Westphalian and the Stephanian, in our Upper Coal- 

 Measures. 



It appears to be a moot point at present, how far any equivalents 

 of the Lower Coal-Measure horizon of the Pennine and Scottish 

 series of basins can be recognized in the Continental coalfields of 

 the Artois system, though Prof. Zeiller :! finds that such equiva- 

 lents do occur in the ]N"ord-de-Erance Coalfield and in Westphalia. 

 The great bulk of the measures in Westphalia, Belgium, the Nord 

 de Erance, and to a less extent in the Pas de Calais, appear, beyond 

 doubt, to be Middle Coal-Measures. Certainly in Southern England 

 and South Wales no Lower Coal-Measures have yet been recognized 

 in a palaeobotanical sense, although Middle Coal-Measures are met 

 with in South Wales and in Devon & Cornwall. 



As, however, we follow the line of the Artois-Mendip axis from 

 east to west, it appears that higher and higher horizons are met 

 with, and that deposition in Carboniferous times continued longer 

 towards the west, than in the east. In the Pas de Calais, in 

 Zone C of Prof. Zeiller's 4 classification, we meet with the Upper 

 Transition Measures, and, as has been shown here, these also 

 ■occur in Kent. Farther westwards, in Somerset, and in South 

 Wales (omitting for the moment the Eorest-of-Dean Coalfield, the 

 flora of which I have not yet completely worked out), we find that, 

 in addition to the Upper Transition Measures, a higher zone, that of 



1 Munier-Chalmas & A. de Lapparent (93 1 ) p. 871 ; see also (93 2 ) p. 450. 



2 "Kidston (05). 



:1 Zeiller (94 1 ) pp. 494 & 500. 

 4 Id. (94 L ) pp. 491 & 495. 



