tified in trees from the Carboniferous series of Britain.* T of ordinary Pines occurs in wood from the Coal format of Nova Scotia and New Holland.

The same ordinary structure of Pines predominates in fossil wood of the Lias at Whitby; trunks of Araucar also are found there in the same Lias; and branches, w the leaves still adhering to them, in the Lias at Lyme Reg

Professor Lindley justly remarks that it is an import fact, that at the period of the deposite of the Lias, the ve tation was similar to that of the Southern Hemisphere, alone in the single fact of the presence of Cycadeæ, but the Pines were also of the nature of species now found o to the south of the Equator. Of the four recent species Araucaria at present known, one is found on the east co of New Holland, another in Norfolk Island, a third in Bra and the fourth in Chili. (Foss. Flora, vol. ii. p. 21.)

Whatever result may follow from future investigatio our present information shows that the largest and m perfect fossil Coniferæ, which have been as yet sufficier examined from the Coal formation and the Lias, are refe ble either to the genus Pinus, or Araucaria,‡ and that b

A trunk of Araucarias forty-seven feet long was found in Cragl Quarry near Edinburgh, 1830. (See Witham's Fossil Vegetables, 18 Pl. 5.) Another, three feet in diameter, and more than twenty-four long, was discovered in the same quarries in 1833. (See Nicol on F Coniferæ, Edin. New Phil. Journal, Jan, 1834.) The longitudinal tions of this Tree exhibit, like the recent Araucaria excelsa, small I gonal discs, arranged in double, and triple quadruple rows within longitudinal vessels; so also does a similar section from the Coal-fiel New-Holland.

See Lindley and Hutton's Fossil Flora, Pl. 88. A fossil cone refer to Coniferæ, and possibly to the genus Araucaria, from the Lias of L Regis, is represented at Plate 89 of the same work.

Mr. Nicol states that in fossil woods from the Whitby Lias, concentric layers are distinctly marked on their transverse section, 56a, Fig. 2, a, a) the longitudinal sections have also the structur Pinus (Pl. 56a, Fig. 1.;) but when the transverse section exhibits no tinct annual layers, (Pl. 56a, Fig. 4.) or has them but slightly indica

these modifications of the existing Family of Coniferæ date their commencement from that very ancient period, when the Carboniferous strata of the Transition formation were deposited.

Fragments of trunks of Coniferous wood, and occasionally leaves and cones occur through all stages of the Oolite formation, from the Lias to the Portland stone. On the upper surface of the Portland stone, we find the remains of an ancient forest, in which are preserved large prostrate silicified stumps of Coniferæ, having their roots still fixed in the black vegetable mould in which they grew. Fragments of coniferous wood are also frequent throughout the Wealden and Greensand formations, and occur occasionally in Chalk.*

It appears that the Coniferæ are common to fossiliferous strata of all periods; they are least abundant in the Transition series, more numerous in the Secondary, and most frequent in the Tertiary series. Hence we learn that there has been no time since the commencement of terrestrial vegetation on the surface of our Globe, in which large Coniferous trees did not exist; but our present evidence is insufficient,. to ascertain with accuracy the proportions they bore to the

(Pl. 56a. Fig. 6. a) the longitudinal section has the characters of Araucaria. (Pl. 56a. Fig. 3, 5.) So also those Coniferæ of the great Coal formation of Edinburgh and Newcastle, which exhibit the structure of Araucaria in their longitudinal section, have no distinct concentric layers; whilst in the fossil Coniferæ from the New Holland and Nova Scotia Coalfield, both longitudinal and transverse sections agree with those of the recent tribe of Pinus.

Mr. Witham also observes that the Coniferæ of the Coal formation, and mountain limestone group, have few and slight appearances of the concentric lines, by which the annual layers of the wood are separated, which is also frequently the case with the Trees of our present tropical regions, and from this circumstance conjectures that, at the epochs of these formations, the changes of season, as to temperature at least were not abrupt.

There is in the Oxford Museum a fragment of silicified coniferous wood, perforated by Teredines, found by Rev. Dr. Faussett, in a chalk flint at Lower Hardres, near Canterbury.

relative numbers of other families of plants, in each of t successive geological epochs, which are thus connected wi our own, by a new and beautiful series of links, derived fro one of the most important tribes of the vegetable kingdo

SECTION III.

VEGETABLES IN STRATA OF THE SECONDARY SERIES.*

Fossil Cycadea.

THE Flora of the Secondary Series† presents characte of an intermediate kind between the Insular vegetation the Transition series, and the Continental Flora of the Te tiary formations. Its predominating feature consists in th abundant presence of Cycadeæ, (see Pl. 1, Figs. 33, 34, 35 together with Coniferæ, and Ferns.§ (See Pl. 1, Figs. 3 38, 39.)

M. Ad. Brongniart enumerates about seventy species

* See Pl. 1, Figs. 31 to 39.

† M. Ad. Brongniart, in his arrangement of fossil plants, has formed distinct group out of the few species which have been found in the Re sandstone formation (Gres bigarré) immediately above the Coal. In o division of the strata, this Red-sandstone is included, as an inferior mer ber, in the Secondary series. Five Algæ, three Calamites, five Ferns, a five Coniferæ, two Liliacea, and three uncertain Monocotyledonous plan form the entire amount of species which he enumerates in this sm Flora.

See also Jæger ober die Pflanzenversteinerungen in dem Bausandstein v Stuttgart, 1827.

We again refer to Witham's Account of Coniferæ from the Lias, in E observations on Fossil Vegetables, 1833.

§ A very interesting account, accompanied by figures, showing the i ternal structure of the stems of fossil arborescent Ferns of the Seconda period, is given in Cotta's Dendrolithen, Dresden, 1832; these appear to chiefly from the New red sand-stone of Chemnitz near Dresden.

land plants in the Secondary formations, (from the Keuper to the Chalk inclusive ;) one half of these are Coniferæ and Cycadæ, and of this half, twenty-nine are Cycades; the remaining half are chiefly vascular Cryptogamiæ, viz. Ferns, Equisetacea, and Lycopodiaceae. In our actual vegetation, Coniferæ and Cycadeæ scarcely compose a three hundreth part.*

The family of Cycadeæ comprehends only two living Genera; viz. Cycas, (Pl. 58.) and Zamia. (Pl. 59.) There are five known living Species of Cycas and about seventeen of Zamia. Not a single species of the Cycadeæ grows at the present time in Europe: their principal localities are parts of equinoctial America, the West Indies, the Cape of Good Hope, Madagascar, India, the Molucca Islands, Japan, China, and New Holland.

Four or five genera, and twenty-nine species of Cycadeæ, occur in the fossil Flora of the Secondary period, but remains of this family are very rare in strata of the Transition, and Tertiary series.†

*The fossil vegetables in the Secondary series, although they present many kinds of Lignite, very rarely form beds of valuable Coal. The imperfect coal of the Cleaveland Moorlands near Whitby, and of Brora in Sutherland, belong to the inferior region of the Oolite formation. The bituminous coal of Buckeberg near Minden, in Westphalia, is in the Wealden formation.

The coal of Hoer in Scania is either in the Wealden formation, or in the Green-sand (Ann, des Sciences Nat. tom. iv. p. 200.)

I learn by letter from Count Sternberg, (Aug. 1835.) that he has found Cycadea and Zamites in the Coal formation of Bohemia, of which he will publish figures in the 7th and 8th Cahier of his Flore du Monde primitif. This is, I believe, the first example of the recognition of plants of this family in strata of the Carboniferous series.

During a recent visit to the extensive and admirably arranged geological collection in the Museum at Strasbourg, I was informed by M. Voltz that the stern of a Cycadites in that museum, described by M. Ad. Brongniart, as a Mantellia, from the Muschelkalk of Luneville, is derived from the Lias near that Town. M. Voltz knows no example 'of any Cycadites from the Muschelkalk. Stems and leaves of Cycades occur also in the Lias at Lyme Regis. (Lind. Foss. Fl. Pl. 143.)

The Cycadeæ form a beautiful family of plants whose external habit resembles that of Palms, whilst their internal structure approximates in several essential characters to that of Coniferæ. In a third respect, (viz. the Gyrate Vernation, or mode in which the leaves are curled up at their points, within the buds,) they resemble Ferns. (See Pl. 1. F. 33, 34, 35, and Pl. 58, 59.)

I shall select the family of Cycadeæ from the fossil Flora of the Secondary period, and shall enter into some details respecting its organization, with a view of showing an example of the method of analysis, by which Geologists are enabled to arrive at information as to the structure and economy of extinct species of fossil vegetables, and of the importance of the conclusions they are enabled to establish. Those who have attended to the recent progress of vegetable Physiology will duly appreciate the value of microscopic investigations, which enable us to identify the structure of vegetables of such remote antiquity, with that which prevails in the organization of living species.

The physiological discoveries that have lately been made with respect to living species of Cycades, have shown them to occupy an intermediate place between Palms, Ferns, and Coniferæ, to each of which they bear certain points of resemblance; and hence a peculiar interest attends

The most abundant deposit of fossil leaves of Cycadeæ in England, is in the Oolitic formation on the coast of Yorkshire, between Whitby and Scarborough, (See Phillips' Illustration of the Geology of Yorkshire.) Leaves of this family occur also in the Oolitic slate of Stonesfield. Lindley and Hutton, Foss. Flora, Pl. 172, 175.

In Lindley and Hutton's Fossil Flora, Pl. 136, Figures are given of Cones which he refers to the genus Zamia, from the sand-stone of the Wealden formation at Yaverland on the South coast of the I. of Wight.

M. Ad. Brongniart has established a new fossil genus Nilsonia, in the family of Cycadeæ, which occurs at Hoer in Scania, in strata, either of the Wealden or Green-sand formation; and another genus, Pterophyllum, which is found from the New red sand-stone upwards to the Wealden formation.