356 SECTIONAL TRANSACTIONS.— C. 



Some of the microspore diagrams obtained have proved remarkably similar 

 for samples of the same seam, and different for different seams ; but as 

 a rule such results have only confirmed correlations already evident from 

 visual examination of the seams concerned. The salient features of the 

 diagrams are generally due to the two commonest spore types only (A and 

 Di) ; the former being particularly abundant in the dull bands. 



The distribution of the less abundant spore types is considered of greater 

 interest. When sufficiently detailed examinations of each sample are 

 carried out, it is found that some types have restricted time-ranges, which 

 may eventually prove valuable. For example, type Ci, though never very 

 abundant, is found in all seams down to the Haigh Moor in Yorkshire 

 and the Cockshead in Staffordshire, but not below. 



The micro-preparations on which the work is based are inevitably of 

 indifferent quality. It is therefore felt that in future work on these lines 

 the statistical aspect of the work should not be too strongly emphasised ; 

 attention should be centred rather on the careful definition of species. 



Dr. L. Slater and Mr. J. J. Walker. 



The D.S.I.R. Fuel Research Coal Survey has in many cases obtained 

 useful correlation data through detailed examination of the petrographic 

 composition of the seams concerned. For instance, the Barnsley, Parkgate 

 and Silkstone seams are each banded in a characteristic way ; the main 

 bands being recognisable, in pillar samples, by the naked eye. 



This banding of seams has also been studied microscopically, by means 

 of thin sections of coal ; and it has thus been found that many seams each 

 consist of a series of zones of differing megaspore content. In some cases 

 these zones are of remarkable lateral constancy (e.g. the three above- 

 mentioned seams) ; in others, the constituent zones are less well-defined, 

 but when sufficiently detailed examination is made useful correlation data 

 may still be obtained from them (e.g. Haigh Moor and Beeston seams). 



Most of the megaspore types recorded In this work range throughout 

 the Yorkshire sequence of seams. One, however (Triletes brasserti, Stach 

 and Zerndt), is found only in and above the Haigh Moor seam, thereby 

 affording a useful datum line. 



So far thin sections of coal have proved the only reliable means of deciding 

 on the presence or absence of a megaspore type ; separation methods using 

 Schulze solution have given misleading results. 



Mr. G. A. Kellaway. 



Under the direction of Prof. A. E. Trueman a preliminary investigation 

 has been made of the microspore content of certain South Gloucestershire 

 coals belonging to the Farrington Series. More exhaustive examination 

 may yield further results, but, at present, it would seem that the uniformity 

 in the spore content renders correlation of seams within this series a matter 

 of considerable difficulty. From 75 to 85 per cent, of the spores fall into 

 two categories, subdivisions of which are of doubtful value. 



The comparative uniformity of the flora of the upper part of the West- 

 phalian is in strong contrast to the rapid floral changes seen in the Lower 

 Westphalian ; the value of microspore analysis as a correlative method may 

 be limited by this factor. 



Afternoon. 

 Excursion to Rivington Pike. Leader, Mr. R. C. B. Jones. 



