76 SECTIONAL ADDRESSES. 



ages from Carboniferous to Pleistocene and from regions as remote 

 as Alaska, Spitsbergen, the Oxus, Nigeria, and China. This direction 

 persists through every variety of tectonic relations, but seems most 

 regular in the largest and least disturbed fields. 



Jukes' miner's astonishing statement that ' the slyne faces two 

 o'clock sun ... all over the world ' involves more than is at first glance 

 apparent, for, as a friend has pointed out — and when one gives the 

 matter a thought it is obvious — that two o'clock sun must shine from 

 a quite different compass-bearing in the Northern and Southern Hemi- 

 spheres. Yet the data I have collected confirm generally the miner's 

 declaration in the Southern Hemisphere as well as the North, though 

 exceptions occur that may possess a deep significance. 



Many of the southern coals have no definite cleat, but in such as 

 do display a regular system there is a distinct predominance of the 

 N.E.-S.W. direction, which has a curious inverse relationship with the 

 N.W.-S.E. direction of the Northern Hemisphere. 



With war-time interruptions of my inquiries, and, since the war, 

 a spirit of unrest in the mining world which is not conducive to scientific 

 research, I do not feel that the matter is ripe for full discussion, and I 

 forbear to disclose the speculations as to cause which are confided to 

 my note-books further than to say that I feel persuaded that the cause 

 will be found in some relation to influences, tidal or other, dependent 

 upon the earth's planetary role. I have reason to believe that some of 

 the information sent to me from distant fields went to the bottom of 

 the sea in the submarine war. ^A^hen such deficiencies are made good, 

 and all the data gathered together, will be time enough to invoke the aid 

 of specialists in the department of Mathematics most concerned with 

 questions of this nature. 



Meanwhile I would invite attention to the case of another type 

 of organically formed rock that shares with coal the capacity for early 

 consolidation — namely, limestone. My attention was long ago attractred 

 by a remarkable bed of limestone in the gorge at Gordale. It is, at a 

 guess, 100 feet in thickness, and is distinguished by a remarkable system 

 of vertical joints that split the mass into thin plates ranging from half 

 an inch up to several inches in thickness. Determinations of the direc- 

 tion of jointing are not easily made, as the plates are irregular, but a 

 series of eleven determinations made for me gave a maximum deviation 

 of Hi degrees on each side of the mean value N.41°\V. (true bearing), 

 which agrees remarkably with the jointing of the more normal lime- 

 stones in the, district and also with the jointing of the chalk over large 

 areas of the south-east of England. 



There is a negative aspect of the cleat question which brings it more 

 clearly within the ambit of an inquiry into the physiograpliy of the coal 

 swamps. I allude to the absence of cleat that characterises anthracite 

 the world over, and is the basis for the broad classification of coals in 

 the United States into cubical and non-cubical coals. Upon this absence 

 of cleat is attendant features tliat have been regarded as indicative of 

 conditions prevailing during the formation of the coal, and hence clearly 

 within my terms of reference. 



In the Memoir of the Geologicnl Survey on the Coals of South Wales 



