ples, the skeleton lies in relief, with the arms spread out, LIGN. 158.-CUP-LIKE ENCRINITE. From the Mountain-limestone, Clevedon, as if the creature, while floating at its ease in the water, had been suddenly surrounded and entombed in the mud (Ligns. 157, 158). The elegant plumose encrinite, termed Actinocrinus,* occurs in a beautiful state of preservation in the Mountain-limestone; the form of the original is well represented in the Lign. 156, fig. 2, p. 664. The receptacle of the Actinocrinite is constructed of numerous plates, which in many species are richly ornamented; and some have the surface granulated in a radiating manner, like those of certain varieties of the Marsupite. In another genus, the Cyathocrinus (Lign. 158), the receptacle is very simple, and com posed of but few plates. The ossicula of the columns in the Actinocrinites and Cyathocrinites are round and smooth: a beautiful specimen of the cup-shaped Encrinite is represented, of half the natural size, in Lign. 158. 44. PENTREMITES AND CYSTIDEA.-The species and even genera of the fossil Crinoideat are so numerous, that their bare enumeration would require more space than we can allot to the subject, and I can only notice two other remarkable types. *Signifying the Radiated, or Nave-and-spoke Lily-animal. Pentremites. These Lily-shaped animals seem to hold an intermediate space between the Echinites and the Encrinites. Their receptacle consists of five petaloid divisions united by corresponding series of plates, which meet in a point at the summit. Each petal is divided by a groove, and is perforated near the apex. They have a very short pedicle. These Crinoideans are so abundant in some of the cherty beds of the mountain-limestones of Kentucky,* that the rocks have acquired the name of Pentremital limestone. Six or seven species occur in the mountain-limestone of Yorkshire. Cystidea. In the oldest of the fossiliferous strata there occur certain Crinoideans of a type which is supposed to be restricted to the older paleozoic periods. There are about fifteen species in Britain, chiefly of the genera Echinospharites and Pseudocrinites. These fossils were distinguished by Von Buch† by the name of Cystidea. The receptacle is of an oval form, composed of numerous polygonal plates articulated together, and having the necessary apertures on the side of the cup required by the economy of the animal; it has a short pedicle. The Cystidea are supposed to be destitute of true arms. They comprise several genera, and are among the first forms in which the Crinoidea appear in the natural records of our planet. I must here conclude this very general notice of the Crinoideans, a family which, though of excessive rarity in the present seas, swarmed in the oceans of the earlier epochs, in various modifications of form and structure, comprising numerous genera and species, all of which are now extinct. 45. CONCLUDING REMARKS. From this review of the Polypifera and Crinoidea, we learn that an atom of living jelly floating in the ocean, and at length becoming affixed Say; Journal of the Acad. Nat. Sciences of Philadelphia, for 1820. Transact. Acad. Berlin; and Quart. Journ. Geol. Soc. vol. ii. part 2, Miscell. p. 20; and Austin, ibid. vol. iv. p. 291. to a rock, may be the first link in a chain of events, which after the lapse of ages may produce important modifications in the physical geography of our globe. We have seen that the living polypes in their rocky habitations enjoy all the blessings of existence, and at the same time are the unconscious instruments of stupendous operations, which in afterages may affect the destinies of mighty nations; and that the materials elaborated by their agency, and subsequently consolidated by chemical changes, may become the foundations of Islands and Continents, and constitute new and favourable sites for the abode of future generations of the human race. And when we bring the knowledge thus acquired to bear on the natural records of our planet, and examine the rocks and mountains around us, we find that in periods so remote as to exceed our powers of calculation, similar effects were produced by beings of the same type of organization as those whose labours have been the subject of our contemplation. We are thus enabled to read the history of the past, and to trace the succession of events, each of such duration as to defy all attempts to determine with any approach to probability the period required for its development. In fine, these investigations have shown us the marvellous structure of creatures invisible to the naked eye, their modes of life and action, and the important changes effected in the relative proportion of land and water, by such apparently inadequate agents. They have instructed us, that above, beneath, and around us there are beings so minute as to elude our unassisted vision, yet possessing sensation and voluntary notion, and each furnished with its systems of nerves, muscles, and vessels, and preying upon creatures still more minute, and of which millions might be contained in a drop of water; nay, even that these last are supported by living atoms still less, and so on-and on-until the mind is lost in astonishment, and can pursue the subject no further! Thus are we taught,— "That those living things To whom the fragile blade of grass, And perisheth ere noon, That those viewless beings, Whose mansion is the smallest particle Enjoy and live like man! And the minutest throb, Which through their frame diffuses The slightest, faintest motion, As the majestic laws That rule yon rolling orbs!" SHELLEY. We have contemplated the results produced by these countless myriads of animated forms, the excess of calcareous matter brought into the waters of the ocean consolidated by their influence, and giving birth to new regions; and we have obtained evidence that in the earlier ages of our globe, like effects were produced by similar living instruments. The beds of fossil coral are now the sites of towns and cities, whose inhabitants construct their abodes of the limestones, and ornament their temples and palaces with marbles formed of the petrified skeletons of the zoophytes which lived and died in oceans that have long since passed away! Hence we perceive that He who formed the Universe creates nothing in vain; that His works all harmonize to blessings unbounded by the mightiest or the most minute of His creatures; and that the more our knowledge is increased, and our powers of observation are enlarged, the more exalted will be our conception of His wondrous works! LECTURE VII. THE CARBONIFEROUS SERIES. 1. Introductory. 2. The Carboniferous Series. 3. The Coal-measures. 4. Coal-field of Derbyshire. 5. Coalbrook Dale. 6. Nature of Coal-deposits. 7. Mode of Deposition of the Coal-measures. 8. The Great Dismal Swamp of Virginia. 9. Erect Trees in the Carboniferous Deposits. 10. Upright Trees at Wolverhampton and St. Etienne. 11. Upright Trees in the Coal-measures of Nova-Scotia and Cape Breton. 12. Coalshales and Vegetable Remains. 13. Millstone Grit. 14. Carboniferous Limestone. 15. Derbyshire Lead-mines. 16. Carboniferous Rocks of Devonshire. 17. Trap-rocks and Trap-dikes of the Carboniferous Series. 18. Faults in the Coal-measures. 19. Geographical distribution of the Carboniferous Strata. 20. Carboniferous Rocks of North America. 21. Organic remains of the Carboniferous Series. 22. Organization of Vegetables. 23. Climate and Seasons indicated by Fossil Wood. 24. Microscopical examination of Fossil Trees. 25. Nature of Coal. 26. Liebig on the formation of Coal. 27. Bitumen, Petroleum, and Naphtha. 28. The Diamond. 29. Anthracite, Plumbago, &c. 30. Petrifaction of Vegetables. 31. Artificial Vegetable Petrifactions. 32. Silicification of Vegetables. 33. Fossil Plants of the Coal. 34. Equiscetaceous Plants. 35. Fossil Ferns. 36. Sigillaria. 37. Stigmaria. 38. Lepidodendron. 39. Coniferous Trees and Plants, 40. Flora of the Coal. 41. Atmospheric conditions during the Carboniferous period. 42. Formation of Coal-measures. 43. Coal-measures originating in submerged Lands. 44. Zoophytes and Echinoderms of the Carboniferous Series. 45. Shells of the Carboniferous Series. 46. Crustaceans and Insects. 47. Fishes of the Carboniferous Series. 48. Reptiles of the Carboniferous period. 49. Climate of the Paleozoic Ages. 50. Retrospect, and Botanical Epochs. 1. INTRODUCTORY.-From the contemplation of the changes produced on the earth's surface by the agency of minute beings whose nature and economy are known only to the instructed observer, we resume the geological argument from which we have for a while digressed, and enter upon the examination of the series of strata deposited during the period immediately antecedent to the Permian formation described in the fifth Lecture. The Carboniferous series, so named from its comprising the principal deposits of mineral fuel, consists, in England, of a great triple formation of, 1st (lowest), a group of calcareous |