or lily-shaped animals allied to Star-fish, for peculiar consideration in a future chapter. (See Pl. 47, Figs. 5, 6, 7.) Fossil corallines also abound among the radiata of this period, and show that this family had entered thus early upon the important geological functions of adding their calcareous habitations to the solid materials of the strata of the globe. Their history will also be considered in another chapter.

Remains of Vegetables in the Transition Series.

Some idea may be formed of the vegetation which prevailed during the deposition of the upper strata of the transition series, from the figures represented in our first plate (Fig. 1 to 13). In the inferior regions of this series plants are few in number, and principally marine;* but in its superior regions the remains of land plants are accumulated in prodigious quantities, and preserved in a state which gives them a high and two-fold importance; first, as illustrating the history of the earliest vegetation that appeared upon our planet, and the state of climate

* M. A. Brongniart mentions the occurrence of four species of fucoids in the transition strata of Sweden and Quebec; and Dr. Harlan has described another species found in the Alleghany Mountains.

and geological changes which then prevailed:* secondly, as affecting, in no small degree, the actual condition of the human race.

The strata in which these vegetable remains have been collected together in such vast abundance have been justly designated by the name of the carboniferous order, or great coal formation. (See Conybeare and Phillips's Geology of England and Wales, book iii.) It is in this formation chiefly, that the remains of plants of a former world have been preserved and converted into beds of mineral coal; having been transported to the bottom of former seas and estuaries, or lakes, and buried in beds of sand and mud, which have since been changed into sandstone and shale. (See Pl. 1, sec. 14.) †

* The nature of these vegetables, and their relations to existing species, will be considered in a future chapter.

+ The most characteristic type that exists in this country of the general condition and circumstances of the strata composing the great carboniferous order, is found in the north of England. It appears from Mr. Forster's section of the strata from Newcastleupon-Tyne to Cross Fell, in Cumberland, that their united thickness along this line exceeds 4,000 feet. This enormous mass is composed of alternating beds of shale or indurated clay, sandstone, limestone, and coal: the coal is most abundant in the upper part of the series, near Newcastle and Durham, and the limestone predominates towards the lower part; the individual strata enumerated by Forster are thirty-two beds of coal, sixtytwo of sandstone, seventeen of limestone, one intruding bed of trap, and one hundred and twenty-eight beds of shale and clay. The animal remains hitherto noticed in the limestone beds are almost exclusively marine; hence we infer that these strata were

Besides this coal, many strata of the carboniferous order contain subordinate beds of a rich argillaceous iron ore, which the near position of the coal renders easy of reduction to a metallic state; and this reduction is further facilitated by the proximity of limestone, which is requisite as a flux to separate the metal from the ore, and usually abounds in the lower regions of the carboniferous strata.

A formation that is at once the vehicle of two such valuable mineral productions as coal and iron, assumes a place of the first importance among the sources of benefit to mankind; and

deposited at the bottom of the sea. The fresh-water shells that occur occasionally in the upper regions of this great series show that these more recent portions of the coal formation were deposited in water that was either brackish or entirely fresh. It has lately been shown that fresh-water deposits occur also occasionally in the lower regions of the carboniferous series. (See Dr. Hibbert's account of the limestone of Burdie House, near Edinburgh; Transactions of the Royal Society of Edinburgh, vol. xiii.; and Professor Phillips's Notice of fresh-water shells of the genus Unio, in the lower part of the coal series of Yorkshire; London Phil. Mag. Nov. 1832, 349.) The causes which collected these vegetables in beds thus piled above each other, and separated by strata of vast thickness, composed of drifted sand and clay, receive illustration from the manner in which drifted timber from the existing forests of America is now accumulated in the estuaries of the great rivers of that continent, particularly in the estuary of the Mississippi, and on the river Mackenzie. See Lyell's Principles of Geology, 3rd edit. Vol. iii. Book iii. Ch. xv. and Prof. Phillips's Article Geology in Encyclopædia Metropolitana, Pt. 37, page 596.

this benefit is the direct result of physical changes which affected the earth at those remote periods of time, when the first forms of vegetable life appeared upon its surface.

The important uses of coal and iron in administering to the supply of our daily wants, give to every individual amongst us, in almost every moment of our lives, a personal concern, of which but few are conscious, in the geological events of these very distant eras. We are all brought into immediate connection with the vegetation that clothed the ancient earth, before one-half of its actual surface had yet been formed. The trees of the primeval forests have not, like modern trees, undergone decay, yielding back their elements to the soil and atmosphere by which they had been nourished; but, treasured up in subterranean storehouses, have been transformed into enduring beds of coal, which in these later ages have become to man the sources of heat, and light, and wealth. My fire now burns with fuel, and my lamp is shining with the light of gas, derived from coal that has been buried for countless ages in the deep and dark recesses of the earth. We prepare our food, and maintain our forges and furnaces, and the power of our steam-engines, with the remains of plants of ancient forms and extinct species, which were swept from the earth ere the formation of the transition strata was completed. Our instru

ments of cutlery, the tools of our mechanics, and the countless machines which we construct, by the infinitely varied applications of iron, are derived from ore, for the most part coeval with, or more ancient than the fuel, by the aid of which we reduce it to its metallic state, and apply it to innumerable uses in the economy of human life. Thus, from the wreck of forests that waved upon the surface of the primeval lands, and from ferruginous mud that was lodged at the bottom of the primeval waters, we derive our chief supplies of coal and iron; those two fundamental elements of art and industry, which contribute more than any other mineral production of the earth, to increase the riches, and multiply the comforts, and ameliorate the condition of mankind.

CHAPTER VIII.

Strata of the Secondary Series.

WE We may consider the history of secondary, and also of tertiary strata, in two points of view: the one, respecting their actual state as dry land, destined to be the habitation of man; the other, regarding their prior condition, whilst in progress of formation at the bottom of the waters,