264 



THE GEOLOGIST. 



whicli tliey may nevertheless by sinkings be accessible, as in the case of 

 the vast accession of mineral wealth added, in the last twelve years, to the 

 Westphalian coal-field, by the explorations carried through the covering 

 of cretaceous rocks which clothe the northern side of the coal-fiekl The 

 remarkable pit lately completed by the Duke of JN'ewcastle, at Shireoak, 

 was another example. At a distance of several mxiles from any visible 

 coal-measures, it had pierced the IsTew Eed Sandstone and Magnesian 

 Limestone, and reached the "top-hard" coal at 515 yards in depth. 



Eeferring to the principal families of plants which are found either in, 

 or associated with, the coal, he endeavoured to show that their occurrence 

 throws a light on the origin of the coal-seams, a knowledge which becomes 

 an important guide in enabling us to judge of the continuity of some fields. 

 The position of the stigmaria in the under-clay or floor of the seam, and of 

 the stems of sigillaria, lepidodendron, calamites, etc., in the roof strata, 

 point to the probability of the growth of the vegetable matter in situ. 

 The existence of numerous upright stems, and especially those occurring 

 so often and so dangerously to the miners in the roof of certain coals, is a 

 strong confirmation of the gradual depression of the tract in which these 

 plants grcAV ; and Goppert has shown that the careful examination of a 

 number of seams proves the existence in the coal itself of every family of 

 plant which has been met with in the coal-measures. 



Thus much had referred to the true Carboniferous period, in which it is 

 commonly supposed that a vigorous vegetation first arose, but the speaker 

 described his finding, a few months since, in the Laxey lead and copper 

 mine, in the Isle of Man, at 120 fathoms deep, a seam of anthracite coal, 

 three to four inches thick, in the midst of ancient schists, probably Lower 

 Silurian. He then noticed the coaly and lignitic beds in newer formations, 

 especially the Tertiary " brown- coal," which in Continental, and especially 

 in Southern Europe, attains to great importance. The excellent preserva- 

 tion of the vegetable remains in the lignite has enabled Professors linger 

 and Heer to make comparisoii with existing floras ; and these authors show 

 that the Tertiary flora had nothing in common with our present flora in 

 Europe, but had an extraordinary resemblance to that of modern North 

 America. This was especially to be noticed in closely similar species of 

 the genera Lig_uidamhar, Liriodendron, Pavia, Nyssa, Sobinia, Taxo- 

 dium. Sequoia, Jiiglans, Glycyrrhiza, Cercis, Laurus, RJiododendron, 

 Cissus, and certain oaks and pines. There was hence, the speaker thought, 

 no retreating from the conclusion, that at that portion of the Tertiary pe- 

 riod a land communication existed between America and Europe. Frag- 

 ments of that land, with relics of the same Tertiary flora, he considered 

 still {>xistcd in Iceland and the Azores, ^\ith their surturhrand and lignites ; 

 aud thus the existence of that Atlantis, which is generally set down as a 

 dream of the poets, was, according to his views, supported by the studies of 

 the geologist. A relation of this kind at a comparatively recent period, 

 throws a light on the causes of phenomena belonging to an earlier epoch, 

 and enabled the forming of conclusions, if not upon the absolute contem- 

 poraneity of certain beds or groups of coal-measures, at all events upon 

 the physical connection within a given period of the agencies which were 

 forming coal not only in the various fields of Europe, but also in ]S'orth 

 America. 



Glasgow Geological Society.— ilfcn/ 10^/^.— The members had an 

 excursion to the hills of Greenock and to Loch Thorn. The hills, 

 generally speaking, are of igneous rock ; towards their fi^ont they were 

 found to be principally of a fiue variety of amygdaloids, containing nodules 

 of crystallized quartz, and silicates of magnesia, with indications of zeolitic 



