powers of observation are enlarged, the more exalted will be our conceptions of His wondrous works. Thus, in the eloquent language of Dr. Chalmers," while the telescope enables us to see a system in every star, the microscope unfolds to us a world in every atom. The one instructs us that this mighty globe, with the whole burthen of its people and its countries, is but a grain of sand in the vast field of immensity-the other, that every atom may harbour the tribes and families of a busy population. The one shows us the insignificance of the world we inhabit-the other redeems it from all its insignificance, for it tells us that in the leaves of every forest, in the flowers of every garden, in the waters of every rivulet, there are worlds teeming with life, and numberless as are the stars of the firmament. The one suggests to us, that above and beyond all that is visible to man, there may be regions of creation which sweep immeasurably along, and carry the impress of the Almighty's hand to the remotest scenes of the Universe-the other, that within and beneath all that minuteness which the aided eye of man has been able to explore, there may be a world of invisible beings; and that could we draw aside the mysterious curtain which shrouds it from our senses, we might behold a theatre of as many wonders as astronomy can unfold; a Universe within the compass of a point, so small as to elude all the powers of the microscope, but where the Almighty Ruler

of all things finds room for the exercise of his attributes, where he can raise another mechanism of worlds, and fill and animate them all with the evidence of his glory."*

This lecture was illustrated by an extensive collection of recent and fossil corals; and specimens of living actiniæ and zoophytes, from the neighbouring sea. Among the former were fine examples of caryophylliæ and meandrinæ, contributed by Mrs. Robertson; fungiæ, by Miss Crofts; madreporæ, dendrophylliæ, and astreæ, by Lady Mantell; agariciæ, by Miss Ellen Gladwin; gorgoniæ and milleporæ, by Miss E. Mahony, and William Tennant, Esq.; flustra foliacea, by Robert Hannay, Esq.; and sarcinulæ, turbinoliæ, and milleporæ, by Rev. T. Trocke.

LECTURE VII.

1. Introductory remarks. 2. The carboniferous system. 3. The coal measures. 4. Coal-field of Derbyshire. 5. Coalbrook dale. 6. Coalshales, and vegetable remains. 7. Carboniferous, or mountain limestone. 8, Derbyshire lead mines. 9. Carboniferous system of Devonshire. 10. The Devonian system, or old red sandstone. 11. Geographical distribution of the carboniferous system. 12. Volcanic rocks of the carboniferous system. 13. Trap-dikes of the carboniferous system. 14. Organic remains of the carboniferous system. 15. Organization of vegetables. 16. Coniferous trees. 17. Climate and seasons, indicated by fossil wood. 18. Vertical trees in carboniferous strata. 19. Trunks of coniferæ in Craigleith quarry. 20. Microscopic examination of fossil trees. 21. Nature of coal. 22. Mineral oil, naphtha, and petroleum. 23. Bitumen, amber, and mellite. 24. The diamond. 25. Anthracite, cannel coal, and plumbago, or graphite. 26. Nature of petrifaction. 27. Artificial petrifactions. 28. Different states of the fossilization of wood. 29. Hazelnuts filled with spar. 30. Silicification, or petrifaction by silex. 31. Plants in agates, &c. 32, Plants of the coal formation. 33. Fossil mare's-tail, or equisetum. 34. Fossil ferns. 35. Sigillariæ, or fossil arborescent ferns. 36. Lepidodendron. 37. Fossil club-moss, or lycopodites. 38. Stigmaria. 39. Seed-vessels in coal. 40. Coniferæ. 41. Review of the carboniferous flora. 42. Formation of new coalmeasures. 43. Corals and crinoidea of the carboniferous system. 44, Shells of the carboniferous system. 45. Crustacea. 46. The limulus, or king-crab. 47. Trilobites. 48. The eyes of the trilobite. 49. Insects of the coal formation. 50. Fishes of the carboniferous and Devonian systems. 51. Retrospect-the flora of the ancient world.

1. INTRODUCTORY REMARKS.― The examination of the recent and fossil zoophytes, which formed the subject of the last discourse, will enable us to comprehend many of the phenomena relating to the

ancient coralline rocks hereafter to be noticed. I now resume the geological argument from which we have for a while digressed, and hasten to the consideration of the carboniferous system, which in the stratigraphical arrangement (page 194, Pl. VII.) succeeds the saliferous deposits described in the fifth lecture.

The strata comprised in the carboniferous system, so named from its being the great depositary of that important substance called coal, consist of sandstones more or less felspathic, of dark bituminous shales, and coal; and of grey limestones: they admit of three natural divisions. The uppermost is composed of a vast number of alternations of coal, shale, ironstone, and sandstone; the middle, of chert, sandstone, quartzose conglomerates, and limestone, with immense quantities of shells, polyparia, crinoidea, and other marine exuviæ; and the lowermost, of sandstones and conglomerates, generally of a dull red colour, and resembling, in their lithological characters, those of the new or upper red sandstone. I propose to describe-firstly, the general characters of the strata, and their geographical distribution; secondly, the nature of the coal and of the fossil plants, which are scattered through the carboniferous rocks; thirdly, the animal remains; and lastly, review the flora of the ancient world.

2. THE CARBONIFEROUS SYSTEM.-The followig tabular arrangement will convey a general idea

of the characters and relations of this group of deposits.

1. THE COAL MEASURES.

(The uppermost in the series.)

Sandstone, shale, and numerous beds of coal; with layers of ironstone irregularly stratified, abounding in terrestrial plants.

Beds of limestone, with fresh-water shells.

Total thickness, 1000 yards.

2. THE CARBONIFEROUS, OR MOUNTAIN LIMESTONE.

Millstone grit, sandstone, shale, and coal, with plants. Limestone and flagstone, abounding in crinoidea, with plants. Lower, or scar-limestone, with zoophytes in profusion, crinoidea, productæ, spiriferæ, orthoceratites, ammonites, goniatites, bellerophon, trilobites, &c. Total thickness, about 800 yards.

3. OLD RED SANDSTONE, OR MARL.

(DEVONIAN SYSTEM, of Professor Sedgwick and Mr. Murchison.*) Quartzose conglomerates, and silicious sandstones, without organic remains.

Flagstones, marls, and concretionary limestones, provincially termed cornstone; laminated reddish and green micaceous sandstones, called tilestones. Fishes, orthoceratites, nautili, and several genera of mollusca occur, but organic remains are comparatively rare.

Total thickness estimated at 3500 yards.

Such is a synoptical view of the strata usually comprehended in this series; but the recent obser

* Annals of Philosophy, No. 89, p. 259.