yol. 59.] fossil flora of the cumberland coalfield. 23 



Discussion. 



The President pointed out that, although the Carboniferous was 

 the thickest system in Britain, and had been longest studied, 

 geologists were still very far from having arrived at any universally 

 applicable means of establishing the detailed chronological parallelism 

 of the members of the sequences developed in the separate Carboni- 

 ferous areas. Prom the lithological point of view, the groupings 

 associated with the work and publications of Prof. Hull were 

 perhaps of the best available working value. But from the strictly 

 chronological point of view, the only definite conclusion that appeared 

 yet to be regarded as satisfactorily established was that the Carboni- 

 ferous as a whole was separable into a Lower and Upper division at 

 the base of the Millstone Grit, a result especially due to the researches 

 of Dr. Traquair among the Carboniferous fishes. Of the possible 

 zonal divisions of the Lower Carboniferous, little or nothing was as 

 yet known. But the endeavour to separate the Upper Carboniferous 

 into chronological divisions by means of their characteristic plants 

 — with which were associated especially the names of Stur on the 

 Continent and Kidston in Britain — had now reached a stage which 

 gave every promise of success. It was pleasant to learn that the 

 Author of the paper found that the Upper Carboniferous plants 

 studied by him in the Whitehaven Coalfield had not only a vertical 

 distribution corresponding to that ascertained elsewhere, but they 

 were of value here also as aids in the stratigraphical correlation of 

 their containing beds. He did not gather from the Author's remarks 

 whether the so-called 'Millstone Grit' of the Whitehaven Coalfield 

 could be definitely accepted as such. He believed that the sug- 

 gested parallelism of the Whitehaven Sandstone with the Lower 

 Pennant Grit of South Wales was not only novel, but an advance of 

 interest and importance. 



The Secretary, by permission of the President, read the following 

 extracts from a letter received from Dr. Wheelton Hind : — 



' I don't at all know what conclusions Mr. Newell Arber may have arrived at as to 

 the age of the Cumberland Coalfield, but just recently I have been examining a 

 series of lamellibranchs, collected by Miss J. Donald, from the All Hallows coal-pit, 

 which is some little way from Aspatria, in the northern part of the Cumberland 

 Coalfield, and I found Carbonicola acuta, C. aquilina, and Anthracomya WilUam- 

 soni among them. The latter is important, as regards its position both in South Wales 

 and the North Staffordshire Coalfield, and points to seams low down in the series. The 

 only bed in which it occurs in North Staffordshire is the Hard-Mine coal, which is 

 generally included in the Lower Coal-Measures ; but that subdivision is in North 

 Staffordshire a very arbitrary one, and I should prefer to make the division between 

 Middle and Lower, just below this Hard-Mine seam. The division is as unnecessary 

 as it is arbitrary. I have never in any coalfield found A. WilUamsoni much off the 

 same line, and consider it a good and reliable index of position. The other two 

 lamellibranchs obtained at All Hallows are found at, above, and below the horizon 

 of A. WilUamsoni.'' 



Prof. Hull concurred with the President's statement that the 

 paper was of great interest and value. The list of fossil plants 

 produced by the Author clearly established the Upper Carboniferous 

 age of the Whitehaven Sandstone. He questioned, however, very 

 much whether it could be regarded as the representative of the 

 Pennant Grit of South Wales and Somerset, which he regarded 



