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certain, on examination, that they are not very large succulent plants, such as we now call Cactus. following is an account given of one of these trees. "In a quarry of sandstone belonging to the coal formation on which Glasgow is built, in the neighbourhood of that. city, it is stated, that the quarry men came upon the cast of a tree, in situ, just as if it had been growing. The trunk is about twenty-six inches in diameter, not quite round, but somewhat oval, so that the north and south diameter is several inches longer than the east and west diameter. The body itself of the tree is composed of sandstone precisely similar to the rest of the quarry; but the bark has been converted into perfect cherry: coal, which adheres firmly to the tree, and renders it easy to remove the rock with which it is incrusted. About three feet of the bottom part of the tree has been uncovered: this portion is situated about forty feet below the surface of the earth, in a solid quarry of sandstone. The upper part of the trunk and branches has not been discovered; indeed it is some time since the upper portion of this quarry was removed. The roots may be seen dipping down into the earth, precisely as the roots of living trees do. Four very large roots may be seen issuing from the trunk, and extending, some of them, about a foot, before they are lost in the surrounding stone. There is nothing to distinguish the species of tree, of which the mould has been here preserved. From the appearance of the roots, it is obvious that it was not a fir; it had more resemblance to a beech: the bark has been so completely bituminized, that its usual characters are effaced." Notwithstanding this description seems to be of a tree, Geologists are much of opinion that it is not so, and that, at the period of this deposit, there were no trees. The size which these fossil plants have attained, compared with that of the Cactus known in Europe, must, as in the fossil last mentioned, lead to a doubt as to this opinion of their, agreement with the recent Cactus. But to be enabled VOL. VII.

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to form a correct judgment on this point, it is necessary to know the state in which these plants exist, where the soil and climate are such as to allow them to develope themselves in their native luxuriance. The researches of Humboldt, in the equinoctial regions, supply us on this head with the most appropriate and satisfactory information. The following detached observations of that philosopher will show not only the size to which these plants may arrive, but the vast tracts which, under favourable circumstances, they may overrun, as well as the great probability of their having been the first vegetable clothing of the earth. "The hill of calcareous breccia, which we have just regarded as an island in the gulph, is covered with a thick forest of columnar Cactus and Opuntia, some thirty or forty feet high, covered with lichens, and divided into several branches in the form of candelabra, wearing a singular appearance. Near Maniquarez, at Punta Araya, we measured a Cactus, the trunk of which was four feet nine inches in circumference. The European, acquainted only with the Opuntia in our hot-houses, is surprised to see the wood of this plant become so hard from age, that it resists for centuries both air and water, and that the Indians of Cumana employ it in preference for hords and door-posts. At San Fernando, the soil abounds with aquatic plants, with sagittate (arrow-shaped) leaves, and he remarks that some of these succulent plants are from eight to ten feet high. In Europe their assemblage would be considered a little wood. He also mentions a kind of Bamboo which the Indians call Jagua, which is found near San Fernando, more than 40 feet in height. These, he observes, cannot but remind the admirer of fossils, of the vast fossil Bamboos which are found in the Sandstone accompanying Coal."

ANNE.-I am almost lost in the novelty of these ideasthat a whole world of vegetation should thus lie entombed-and the forms so well preserved as to become subjects of botanical examination.

MRS. L.-"In the argillaceous and bituminous Slate forming the floors and roofs of coal mines, are vast collections of the bituminized remains of Gramina, Junci, Cryptogamia, and numerous other plants, agreeing in their general characters with those of succulent plants, but differing from the recent ones known in Europe, by their vast magnitude, and by the richness of the ornamental markings which appear on their trunks. Description cannot succeed in an attempt to give an idea of the beauty and varieties of the figures which are displayed on the surface of many of those fossils, and which have been supposed to owe their markings to the different trees of supposed antediluvian existence". I have copied from a plate one of the most extraordinary of these fossil vegetables, bearing, as you will see, little resemblance to any plant we know; yet looking so decidedly like a plant, we should immediately pronounce it to be a part of one. Fig. 1 is the external, Fig. 2 the internal appearance.

MAT. Have any specimens been found that are known to be the same that now exist?

MRS. L.-Possibly some few, or at least so near as to enable the botanist to determine the Class and Genus in which to arrange them. "By these facts we learn, that, at some remote and very early period of the existence of this planet, it must have abounded with plants of the succulent kind; and, as it appears from their remains, in great variety of forms and luxuriance of size. These, from what is discoverable in their structure, beset with setæ and spines, were not formed for the food of animals -nor, from the nature of the substances of which they were composed, were they fitted to be applied to the various purposes to which wood, the product of the earth at a subsequent period, has been found to be so excellently adapted by man. Their remains, it must also be remarked, are now found in conjunction with that substance which nature has, in all probability, formed from them; and which by the peculiar economical modifica