264 
THE GEOLOGIST. 
which they 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-field. The 
remarkable pit lately completed by the Duke of Newcastle, at Shireoak, 
was another example. At a distance of several miles from any visible 
coal-measures, it had pierced the New E-ed Sandstone and Magnesian 
Limestone, and reached the " top-hard " coal at 515 yards in depth. 
Keferring 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 grew ; 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 comparison 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 Liquidamhar, Liriodendron, Pavia, Nyssa, Bohinia, Taxo- 
dium, Sequoia, Juglans, Glycyrrhiza, Cercis, Laurus, Rhododetidron, 
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 existed in Iceland and the Azores, with their surturhrand and lignites ; 
and 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 North 
America. 
Glasgow Geological Soctety. — May 10th. — The members had an 
excursion to the hills of Greenock and to Loch Thorn. The hills, 
generally speaking, are of igneous rock ; towards their front they were 
found to be principally of a fine variety of amygdaloids, containing nodules 
of crystallized quartz, and silicates of magnesia, with indications of zeolitic 
