188 Reports and Proceedings — 



spores did was uncertain ; it "was true they could be detected in it. 

 In the second bed of the shallow seam they had a very different 

 coal from the upper one. It was made up almost as a whole of 

 bydrocarbonaceous material. Very few spores could be detected. 

 It was possible that the scarcity of these objects might be due to 

 decomposition ; but the author's investigations seemed to show that 

 spores resisted decomposing influences more effectually than wood- 

 tissue, which seemed to account for the fact that where they occur, 

 they stand out in bold relief against the other material composing 

 the coal. Below the central bed of the shallow seam came the main, 

 division. In it the author detected a large accumulation of spores, 

 but hydrocarbon formed a fair proportion of the mass. The author 

 referred to other seams of coal from various parts of England, and 

 pointed out the structure of each bed composing them. The con- 

 clusions on the evidence elicited from his investigations were (1) 

 that some coals were practically made up of spores, others were not, 

 these variations often occurring in the beds of the same seam ; (2) 

 the so-called bituminous coals were largely made up of the substance 

 which the author termed hydrocarbon, to which the wood-tissue un- 

 doubtedly contributed. 



An appendix to the paper, written by Prof. Harker, Professor of 

 Botany and Geology at the Eoyal Agricultural College, Cirencester, 

 dealt with the determination of the spores seen in Mr. Wethered's 

 microscopic sections. Taking the macrospores, the resemblance to 

 those of Isoetes could not fail to strike the botanist. He had 

 procured some herbarium specimens of Isoetes lacustris in fruit, and 

 compared the spores with those from the coal. When gently crushed, 

 the identity of the appearance presented by those forms from the 

 coal was very striking. The triradiate markings of the latter were 

 almost exactly like the flattened three radiating lines which mark 

 the upper hemisphere of the macrospores of Isoetes lacustris. The 

 writer therefore concluded that the forms in the coal were from a 

 group of plants having affinities with the modern genus Isoetes, and 

 from this Isoetoid character he suggests the generic title of Isoetcides, 

 pending further investigation. 



2. " On Strain in connexion with Crystallization and the Develop- 

 ment of Perlitic Structure." By Frank Rutley, Esq., F.G.S. 



In a paper read before the Society and published in the " Quarterly 

 Journal" (vol. xxxvii. p. 391) some observations were made upon 

 microscopic areas of depolarization in an obsidian tuff from Montana, 

 U.S. The paper now read related to a further examination of similar 

 phenomena in an obsidian from Java. The glass adjacent to the 

 numerous crystals occurring in this rock exhibits depolarization, as 

 in the case of the Montana tuff. In some instances a perlitic struc- 

 ture surrounds the crystals, and the depolarization then ends abruptly 

 at the fissure. One instance is described in which such a fissure 

 only partially encircles a crystal, and the depolarization is then seen 

 to end abruptly at the fissure and also to fade away gradually in 

 those directions which are not thus limited. The conclusion was, 

 that the depolarization is the result of strain, and that the perlitic 



