58 
the Middle Coal Measures (Houiller Moyen), and the Inferior 
Coal Measures (Houiller inférieur). 
His views on the subject seem to be exactly in accordance with 
those of Mr. Robert Kidston, one of the best authorities on coal 
plants, who, in a paper “On the Fossil Flora of the Radstock 
Series of the Somerset and Bristol Coal Field,” read before the 
Royal Society of Edinburgh, on the 4th of April, 1887, has 
stated as follows:—‘* The Radstock series belong to the upper- 
“most beds of the British Coal Measures. Beds of the same age 
“Cas the Radstock series appear to be absent from France. Their 
“position is evidently between the Upper and Middle Coal 
“«‘ Measures of the French coal fields.” Mr. Kidston has also given 
the probable equivalents of the French and British carboniferous 
rocks, as follows :— 
France. Britain. 
Upper Coal Measures (Houiller 
Supérieur and Ss 
inférieur) 
Adbsenitir shaecnuwetaeen ste eenees.. 625: Radstock Series (Upper Coal 
Measures of Britain) 
Middle Coal Measures (Houiller f Middle Coal Measures 
Moyen \ Lower Coal Measures 
) ( Carboniferous 
Inferior Coal Measures | Lower | Limestone Series 
(Houiller inférieur) f Carboniferous | Calciferous Sand- 
} L stone Series 
In an able letter to Mr. Kidston, M. Zeiller has given in detail 
the facts on which the foregoing classification is based, which he 
concludes as follows :—‘ From this the Radstock series represents, 
“jin my opinion, a horizon that we have not in France, but 
“corresponds to the interval between the end of the coal deposits 
‘in the North of France and the beginning of the coalfields of 
*‘the centre.” And in a later letter M. Zeiller further says -— 
“ The mixture they (the Radstock Series) present of Upper Coal 
“ Measure species with Lower Coal Measure species is unquestion- 
