SECTIONAL TRANSACTIONS.—C. 369 
North Sea-Great Eastern Interglacial, which was a period of elevation and 
erosion. 
The approximate contemporaneity of the Clactonian and Acheulian in the 
Breckland area may be considered as established by the finding of both 
cultures in an unabraded state in the same gravels. 
Mr. S. HazzLeDINE WARREN. 
The opinion is expressed that these disputed items in prehistory are not 
human industries at all, and, if this be so, then the constructive problem of 
their correlation does not arise. Prehistory has been carried away by the 
glamour of its superstructure and has never devoted proper attention to its 
foundation: that is, to the reliable identification of the flint industry. 
It is not possible to discuss the evidences in detail, but it is claimed that 
comparison with the true facts of natural flaking shows that the whole of 
the supposed Crag and allied industries are the products of natural agencies. 
The association of the striation, bruising, and the supposed human 
flaking that is characteristic of the stone-bed is referred to a common cause 
—namely to the grounding of floating ice upon the floor of the shallow 
Crag sea. 
Dr. W. B. WricuHT. 
Friday, September 6. 
PRESIDENTIAL ApprRESss by Prof. G. HicKLiNc on Some geological aspects 
of recent research on coal (10.0). (See p. 47.) 
SECTIONAL Discussion with speakers from Section B (Chemistry), on 
The development of rank in coal and its geological implications (11.0). 
Prof. W. G. Fearnsipes, F.R.S. 
The idea of rank in coal as a measure of the stage of its alteration has 
grown up gradually with the recognition that peat, lignite, bituminous 
coals and anthracite are members of a continuous series of products 
derived from vegetable debris by loss of volatile matter. No geologist 
believes that this alteration has taken place either wholly under surface 
conditions or at temperatures comparable with those required in the manu- 
facture of coke. Intermediate and progressively rising temperatures were 
involved. 
Hilt’s law, ‘in a single vertical section the deeper seams are of higher 
rank than the upper,’ limited by application only to similar kinds of vegetable 
debris, is found true for British coalfields. A rise of one degree Centigrade 
per 100 ft. of depth is the present ruling geothermic gradient in Midland 
coalfields ; and the question is put whether such gradient continued through 
the maximum measured thickness, 10,000 feet, of English Coal Measures, 
can account for observed variations of rank. 
It is stated that there is general correspondence between the pattern of 
variation of thickness—isohypses—of the upper zones of Coal Measures 
as they were deposited, and the distribution of coals of coking quality in 
the Midlands, more particularly in Yorkshire. It is suggested that burial 
under 5,000 ft. of Red Measures in Warwickshire brought about the con- 
version of vegetable debris there into low rank bituminous coals. Rank of 
coals in the concealed coalfield in Yorkshire and Nottinghamshire shows 
