NOTES AND COMMEN' 



SPLITTING OF COAL SEAMS 



In the Transactions of the Institution of Mining Engineers, 

 Vol. LIV., pt. 3, Prof. P. F. Kendall has a paper ' On the 

 Splitting of Coal-seams by Partings of Dirt. Part I. — Splits 

 that rejoin.' He states : — The splitting of coal-seams by the 

 intercalation of wedges or lenses of sedimentary material 

 offers one of the most disconcerting problems confronting the 

 mining engineer. There is probably no important seam in the 

 great midland Coalfield but exhibits the phenomenon in one 

 or another of its forms. Two types of split can be recognized. 

 One type had its cause and origin in local depressions of the 

 original area of coal-accumulation, converting it from a con- 

 dition of swamp-forest unto actual lagoon, thereby drowning 

 the contributory plants and arresting further growth until the 

 deposition of sediment had again built up a platform upon 

 which the vegetation could re-establish itself. They may be 

 termed ' tectonic splits ' — that is, splits brought about by 

 earth-movements. 



AND THEIR CAUSES. 



After carefully reviewing the evidence, he concludes that : — 

 (i) That linear splits in coal-seams that rejoin are usually 



erosion phenomena, and not, as Bowman supposed, tectonic in 



origin. 



(2) That the common phenomenon of the arching of the 

 upper portion of the seam over the dirt-parting is the result of 

 the relative incompressibility of the sedimentary material. 



(3) That the W'hitwood-Ackton Hall Split marks the 

 course of a stream traversing the area during the formation of 

 the " Silkstone ' (Middleton Main) Coal. 



(4) That the stream was probably the same as that of 

 which traces are found at Allerton Bywater, and possibly the 

 same as that at Woodlesford, Swillington and Newsam Green, 

 but probably not that at Colton. 



(5) That the split at Wheldale and Fryston is of somewhat 

 earlier date than the Whitwood Split, and that, if of the same 

 type, it is on a vastly larger scale. 



The discoidal splitting at Water Haigh was due, the writer 

 believes, to a different cause, but the infilling was accomplished 

 by the overflow of muddy water from the adjacent river. 



AGRICULTURAL PESTS.* 



In this excellent report the author has very thoroughly 

 considered the subject from all points of view and no doubt 



* Report 071 Agyicidtural Damage by Vermin and Birds in the Counties 

 of Norfolk and Oxfordshire in 1916. By R. T. Gunther, M.A., F.Z.S. 

 Oxford University Press. 92 pp., 2/6 net. 



1918 Nov. 1. 



