contemporaries, bears, hyenas, tigers, and other carnivora of species now extinct.

Fourthly-that there was therefore a period immediately preceding the existence of man, when the earth teemed with large herbivorous animals, which roamed through the primeval forests unmolested, save by beasts of prey. Numerous species and entire genera have been swept away from the face of the earth,-some by sudden revolutions, others by a gradual extinction,—while many have been exterminated by man.

Lastly-that these various strata, whether formed in the beds of lakes or rivers, in estuaries, or in the depths of the ocean, have been elevated above the level of the sea, and now constitute fertile countries, supporting the busy population of the human

race.

I have thus endeavoured to interpret one page of the ancient physical history of our planet, and to explain the records of one epoch in geological chronology. We have entered upon the confines of the past, and already we find ourselves surrounded by an innumerable population of unknown types of being, not as dim and shadowy phantoms of the imagination, but in all the reality of form and structure, and bearing the impress of the mighty changes of which they constitute the imperishable memorials. We have again witnessed the effects of the continual mutations of the land and water,

have seen that our present plains and valleys were submerged beneath the ocean, at a period when large mammalia, apparently unrestricted by existing limits of climate, were inhabitants of regions which are now no more-and we have obtained additional proof that

New worlds are still emerging from the deep,
The old descending in their turn to rise!

Even in this early stage of our progress, we have conclusive evidence of the extinction of whole tribes of animals, equally admirable in their adaptation to the conditions in which they were placed, as the races which now exist. And delightful it is to the geologist, to find that this fact, which but a few years since was received with hesitation by most, and condemned and rejected by many, is now adduced by the moralist and the divine, as affording new proofs of the wisdom and overruling providence of the Eternal. Reflecting on these phenomena, the mind recalls the impressive exclamation of the poet

My heart is awed within me, when I think
Of the great miracle which still goes on
In silence round me-the perpetual work
Of THY creation, finished, yet renewed
For ever!

LECTURE III.

1. Introductory remarks. 2. Substances composing the crust of the globe. 3. Crystallization. 4. Stratification. 5. Inclined and vertical strata. 6. Veins and faults. 7. Chronological arrangement of the strata. 8. Tertiary formations. 9. Classification of the tertiary strata. 10. Fossil shells. 11. Mineralogical characters of the tertiary system. 12. Newer tertiary or pliocene deposits. 13. Crag of Norfolk and Suffolk. 14. The Sub-Apennines. 15. Middle tertiary, or miocene deposits. 16. Lower tertiary, or eocene deposits. 17. The Paris basin. 18. The London basin. 19. The Isle of Sheppey. 20. Fossil fruits of the tertiary strata. 21. Upper marine, or Bagshot sand. 22. Artesian wells. 23. The Hampshire or Isle of Wight basin. 24. Alum bay. 25 London clay of the Hampshire basin. 26. Fresh-water strata of the Isle of Wight. 27. Organic remains of the Paris, London, and Hants basins. 28. Fossil plants and zoophytes. 29. Tertiary marine and fresh-water shells. 30. Nummulites, and other cephalopoda. 31. Crustacea and fishes. 32. Fossil birds. 33. Fossil animals of Paris. 34. Palæotheria and anoplotheria. 35. Fossil quadrumana, or monkeys. 36. Tertiary strata of Aix, in Provence. 37. Fossil insects. 38. Lacustrine formation of Eningen. 39. Fossil fishes of Monte Bolca. Tertiary volcanoes of France. 41. Extinct volcanoes of Auvergne. 42. The crater of Puy de Come. 43. Mont Dor. 44. Fresh-water limestone and organic remains of Auvergne. 45. Summary of the geological phenomena of Auvergne. 46. Erosion of valleys by water-currents. 47. Extinct volcanoes of the Rhine. 48. Brown coal formation. 49. Other tertiary strata of Europe, North America, &c. 50. Altered tertiary strata of the Andes. 51. Tertiary saliferous deposit. 52. Retrospect. 53. Concluding remarks.

40.

1. INTRODUCTORY REMARKS.-It is my object in these Lectures to present a general view of the philosophy of Geology, rather than enter at length on the nature and distribution of the materials of which the crust of our globe is composed; and to render the details of geological phenomena subser

vient to an explanation of the laws which the Divine Author of all things has established for the renovation, maintenance, and government of the organic and inorganic kingdoms of Nature. Based as Geology is upon observations of the various physical changes which are now taking place, and on investigations of the natural records of those changes, in periods antecdent to all human history and tradition, the rocks and mountains are the alphabet, the book of Nature the volume, by which the student of this interesting department of science can best learn its important lessons. But to those who cannot examine Nature in her secret recesses, or accompany an experienced teacher to the valleys, or the mountain-tops, lectures illustrated by specimens and drawings, afford, perhaps, the best substitute for the more efficient and delightful mode of instruction.

That we may obtain a clear and comprehensive view of the vast field of inquiry that lies open before us, artificial classifications are necessary in this, as in other departments of science; and without assuming that the arrangement in which the various deposits are grouped by geologists, will not, in the progress of discovery, require considerable modification, it will be necessary, as an introduction to the subjects hereafter to be discussed, to place before you a tabular view of the formations in their presumed chronological order. At the same time it is necessary to bear in mind, that all classifications of this kind

must necessarily involve arbitrary distinctions, and that very possibly it will hereafter be found that we may in some instances have classed as general, what may prove to be merely local phenomena; and have grouped together deposits, which farther investigations may show to be distinct, and separated from each other by vast periods of time. This consideration will not, however, affect those leading principles of modern Geology, which it is my present endeavour to render familiar to the intelligent but unscientific inquirer.

We will now take a general view of the nature of the mineral substances which enter into the composition of the crust of our globe, and briefly notice the laws which regulate the deposition of detritus in the beds of lakes and rivers, and in the depths of the ocean. But, as I have already remarked, it is not my intention to enter on these departments of Geology in detail; the works of Bakewell, Lyell,† Phillips,+

"Introduction to Geology," by Robert Bakewell, Esq. 1 vol. 8vo. 5th edition. This excellent volume should be the

first book in the library of the geological student.

"The Principles of Geology," by Charles Lyell, Esq. F.R.S. 4 vols. 12mo. One of the most interesting works in the English language. "Elements of Geology." 1 vol. By the same author. 1838.

"A Guide to Geology," by John Phillips, Esq. F.R.S. 1 vol. 12mo. The article on Geology, in the Encyclopedia Metropolitana, by the same excellent writer, is in my opinion the best scientific epitome of modern Geology that has yet appeared. "A Treatise on Geology," in 2 vols. foolscap 8vo. by the same author. 1839. A work of great merit.