Oeological Society of London. 187 



clay of various parts of Lancasbire, as at Great Crosby, Innewick 

 Fishery, and the Isle of Whithoi-n. 



These identifications go far towards completing the identification 

 of the rocks represented in the low-level Boulder-clay of Lancashire, 

 and coTifirm the views already expressed by the author that all stones 

 in the Drift of North-western England are derived from the basins 

 of the Irish Sea, and of rivers draining to it, except some stray 

 fragments that may have come from the Highlands of Scotland. 



4. " Eipple-marks in Drift." By T. Mellard Eeade, Esq., F.G.S. 



Amongst published notices of drift-deposits the author has never 

 met with any description of ripple-marks, though, if the drift was 

 formed under water, some should be found. In a spot to which his 

 attention was called by Dr. Callaway, the Old Park Field sand-hole 

 at Ketley, near Wellington, Salop, in a stratified drift-deposit, he 

 had found early in 1883 three distinct beds of ripple-marked lamina. 

 One of the ripple-marks in the highest bed measured 9 inches from 

 crest to crest and 11 inch in height, and had been produced by a 

 wind from the N.W. 



In July, 1883, the author found ripple-marking in hard, fine 

 loamy brown sand underlying a compact mass of Boulder-clay at 

 Tranmere, Cheshire, in one of the approaches to the Mersey Tunnel. 

 The marks were on a sloping bank, and the sand was faulted in 

 places with a throw of from 2 to 4 inches, In the sand shell-frag- 

 ments occurred, some of them being recognizable as those of Turri- 

 tella terebra. Cardium edule, Tellina balthica, and a FhoJas. 



The position of this section in a hollow between higher ground 

 was favourable to the preservation of ripple-markings. The beds 

 undoubtedly are those named by the author the Low-Level Boulder- 

 clays and Sands. 



IIL— March 5, 1884.— Prof. T. G. Bonney, D.Sc, F.E.S., President, 

 in the Chair. — The following- communications were read : — 



1. " On the Structure and Formation of Coal." By E. Wethered, 

 Esq., F.G.S., F.C.S. 



The author, having referred to the work of previous investigators, 

 pointed out that seams of coal do not always occur in one bed, but 

 are divided by distinct partings, some of which, as in the case of the 

 Durham main seam, contain Stigmarice. It was important to notice 

 this feature for several reasons, but especially as the beds of coal, 

 defined by the partings, showed differences both in quality and 

 structure. In the case of the shallow seam of Cannock Chase, they 

 had at the top of a bed of coal 1 foot 10 inches thick, the brown 

 layers of which were made up of macrospores and microspores. 

 The bright layers were of similar construction, except that wood- 

 tissue sometimes appeared, also a brown structureless material, which 

 the author looked upon as bitumen. He, however, objected to that 

 term, and thought that hydrocarbonaceous substance would be prefer- 

 able. What this hydrocarbonaceous material originated from was a 

 question for investigation. In the lower bed of the Welsh " Four 

 Feet" seam wood-tissues undoubtedly contributed to it; whether 



