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ples, which the French chemists had recently discovered in modern marine productions, did not also exist in mineral salt waters issuing from strata which geologists consider to have been formed beneath the sea."

As the saline springs of the red marls rise up through the Lias (Lign. 128), they undergo certain chemical changes. From the decomposition of the sulphate of iron which takes place, a vast quantity of sulphuric acid must be generated, which, reacting on the different bases of magnesia, lime, &c., contained in the strata, forms those sulphates so prevalent in the higher or pyritous beds of the Lias; the oxide of iron being at the same time more or less completely separated. By this means the mineral-waters, which are probably mere brine-springs at the greatest depths, acquire additional medicinal qualities as they ascend to the places whence they flow. At the same time it must be borne in mind that fresh water is continually falling from the atmosphere upon the surface of the Lias clays, and percolating through the uppermost strata.

6. CONGLOMERATES OF THE TRIAS.-The conglomerates of this formation are chiefly composed of pebbles and detritus derived from the destruction of igneous and metamorphic rocks, as slate, quartz-rock, granite, porphyry, &c.; and the fine siliceous sandstones contain a large proportion of such debris. It would, therefore, appear that the sea which deposited the saliferous group was bounded by the rocks of whose ruins it is composed; in like manner as the existence of beaches of flint-pebbles evinces the destruction of former chalk-cliffs.

The rock on which Nottingham Castle is built is a conglomerate formed of the ruins of the ancient rocks of the neighbouring districts. The rounded pebbles of quartz, lydian stone, granite, jasper, porphyry, slate, &c., seem to have originated from rocks formerly connected with the range of Charnwood Forest. Still nearer the Charnwood

hills, the finest sandstone contains fragments of slate. Mr. Bakewell was of opinion that a large proportion of the materials of the Triassic strata was derived from trap and other igneous rocks; and that the red marl was the debris arising from the decomposition of the less indurated volcanic products; hence, probably, the extreme fertility of the soil.*

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7. ORGANIC REMAINS OF THE TRIAS. This formation presents a remarkable contrast with that of the Jurassic, in the paucity of organic remains; for, while the latter teems with marine fossils, the former, throughout immense areas, is almost wholly destitute of any vestiges of animals or vegetables; a proof that the strata were, for the most part, accumulated under conditions unfavourable for the preservation of organic structures. Several Fucoidal plants, between thirty and forty species of Ferns,† nearly twelve of Cycadeæ, and about fourteen referable to Coniferæ, have, however, been obtained and determined. Among these are fronds of a plant bearing some resemblance to the

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LIGN. 129.-FOSSIL PLANT ALLIED TO THE ADDER'S-TONGUE; FROM THE RED MARL, SULZ-LES-BAINS.

(Crematopteris scolopendrioides; one half the natural size.)

Adder's tongue (Asplenium scolopendrium), so common on the banks of our woods and copses; a specimen discovered by M. Voltz exhibits the fructification on the back of the leaf (Lign. 129). But the most characteristic plants of * Introduction to Geology, fifth edition, p. 279.

† Fragments of the large fronds of the Anomopteris Mougeoti, from the Bunter, are figured in the Medals, vol. i. p. 117, and Petrifactions, p. 32.

the Triassic flora are Coniferæ, belonging to a genus named Voltzia, which differ from any now living, but somewhat resemble the Araucaria, or Norfolk Island pine. Fragments

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LIGN. 130.-CONIFERE OF THE TRIAS: FROM SULZ-LES-BAINS.

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of these fossil plants are frequent in the greenish marls near Strasburg: two specimens of portions of branches are figured in Lign. 130; fig. 2 shows the fructification.t Several

From the late Mr. Voltz of Strasburg, by whom they were first discovered.

+ See Essai d'une Flore du Grès Bigarré; par M. Ad. Brongniart, Ann. Sciences Nat., 1828.

species of equisetaceous plants (Calamites and Equisetites) abound; one of which is probably the E. columnaris of the Lower Oolite.

A very remarkable fossil (Dictyophyllum crassinervum*) has been found in the Triassic sandstone near Liverpool; it is a leaf of considerable size, bearing a striking resemblance to the foliage of some of the thick-ribbed cabbages.† I will only add, that, as a whole, the flora of the Trias, or New Red, presents a general character by which it is separated alike from the vegetation of the older formations below, and of the Lias above, though showing a strong affinity to that of the latter.

8. CRUSTACEA, MOLLUSCA, AND CRINOIDEA.-Crustaceans are rare in the Trias, with the exception of one genus of small bivalved entomostracans, allied to the recent Estheria, and commonly confounded with the molluscan Posidonomyæ. This little Estheria (Posidonomya minuta) is characteristic of the Keuper deposits of England and the Continent; and similar fossils occur in the red shales of Virginia and Pennsylvania. M. Schimper § has figured and described some Xiphosures or Limulus-like Crustaceans from the Trias of Alsace. Polypiferous zoophytes or corals, which are so abundant in the Jurassic formation, are very rare in the Trias. The shells comprise a few species of Cardium, Trigonia, Mya, Plagiostoma, Ostræa, Pecten, Avicula, Terebratula, and other Bivalves, with several Gasteropoda, some Nautili, and numerous Ammonites and Ceratites. The Radiaria consist

The "thick-nerved net-leat.

+ Lindley's Foss. Flora, pl. 201, and Murchison's, "Silurian System," p. 43.

See Mr. Jones's Notice of this fossil in the Quart. Geol. Journ., vol. xii. p. 376.

§ Mém. Mus. Hist. Nat. Strasbourg, vol. iv. 1853.

One or two species occur in the Muschelkalk, and two in the Hallstatt-beds, of the Austrian Alps; Denksch. Akad. Wien, vol. ix. p. 167. ¶ Medals, vol. ii. p. 483.

of a few Star-fishes, Cidarides, Pentacrinites, and Encrinites. Of the latter, a most beautiful form of this family of Crinoi

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LION 31.--THE LILY ECRINITE, FROM THE MUSCHELKALK, NEAR BRUNSWICE. (Encrinus liliiformis.)*

deans is exclusively found in the Muschelkalk, namely, the Lily Encrinite (Lign. 131), so named from the supposed

*First figured and described by Schlotheim; and subsequently, as E. moniliformis, by Miller. Baron von Strombeck has written an interesting description, with illustrations, of the deformities of this species in the "Palæontographica," vol. iv. p. 169.

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