PnOCEKDINGS OF SOCIETIES. 277
Dicfyoxylony This genus — establislied by the author on stems exhibit- ing structure from the coal-measures — was described as consisting of a central vascular axis, with radiating vascular phites, separated by medullary rays, and surrounded by a pareuciiymatous layer containiug free vascular bundles like those of the centre, and the whole enclosed in a bark com- posed of elongated cells, some of which were thickened by secondary de- posits, and arranged in somewhat regular lozenge-shaped meshes, giving to the exterior of the stem a Lepidodendroid aspect. Five species were
described. Mr. Carruthers criticized the descriptions of the author, and
maintained that the stems, though exhibiting certain unimportant varia- tions, could be correlated with the stems of some existing Lycopodiacete.
W. Carruthers, On the Vegetable contents of IMasses of Limestone
occurring in Trappean Rocks in Fifeshire, and the conditions under which they were preserved." The fragments of limestone had been observed on the shore and traced to their place in the rocks by Mr. Grieve. They oc- curred, of different sizes, in a coarse amygdaloidal trap-rock, and the author believed that they were fragments of a peaty layer forming on the surface of the land at the time the volcanic matter was thrown up, and that this layer was broken up, and its fragments, along with masses of clay, sandstone, etc., were enclosed in the volcanic materials when they were arranged under water. The large amount of lime contained in the trap seized on the peat and converted it into limestone before it had time to
decay. The plants were those peculiar to the Carboniferous period.
Professor Williamson believed that the liuicstoue was formed where it was found, and occurred in distinct layers between igneous rocks. The great difference in the hardness of the substance was due to the intluence of the
burning rock. Mr. Pengelly, in his Re])ort on Kent's Cavern, stated
that he had obtained impressions of Ftrns in the stalagmite of the Cave, which Mr. Carruthers had determined to be luxuriant specimens oi Pferis aquiUiia.
Section D. Biology. Depaiitment op Zoology and Botany. — AiKjmt Mil. — Professor AVy ville Thomson, F.R.S., presided, llev. Thomas Brown, F.ll.S.E., " On Fossil Wood from the Base of the Lower Carboni- ferous Rocks at Langton, Berwickshire." The author had obtained from the lower carboniferous rocks of this locality some specimens of fossil wood which seemed to possess certain peculiarities of structure deserving of notice. The transverse section showed a central pith with numerous rays going off" towards the circunderence, and the appearance of annual rings of growth. The longitudinal section showed it to consist of scala- ril'orm tissue, and what appeared to be rays were found to be vascular bundles. The author stated at some length the reasons which led him to think that the dark circles were really analogous to the annual rings of living exogenous trees. He referred also to the combination of crypto- gamic characters with those of exogenous structure. Mr. Carruthers considered that this belonged to a Lepidodendroid ]daid, which had been described by Colta as Diploxyluii. The appearance of annual rings he cousidi'red deceptive, being due to alterations in the speci- mens during fossilization. Professor Thiseltou Dyer, B.A., B.^c,
"On the So-called ' Minucry ' in Plants." He said, in all large natu- ral families of plants there is a more or less distinctly observable general habit or J'uclen, easily recognizable by the practised botanist, but not always as easily to be expressed in words. The existence of
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