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numerous as in Iceland, or have been spread over so large a surface: no part of the island is wholly free from the marks of volcanic agency. The mineral kingdom in Iceland assumes a character highly interesting, on account of the marks of volcanic fire that are so strongly impressed almost on every object. Of this, no one who has visited this island, as far as we know, has given an account that, either for accuracy or extent of view, is at all to be compared with that which is contained in the volume before us. We have only to regret, that there is sometimes too much theory mingled with the description, and too great a tendency to run into polemical discussion. We shall, without any theory, endeavolur to give some account of the leading facts. o rocks which compose the S. W. of Iceland, are all either of the trap formation, or they are real lava. No sandstone, or limestone, or argillaceous strata, were any where visible. Greenstone was the most common species of trap, and in some cases basalt. These rocks are not easily distinguished from lava; and whatever opinion may be entertained of their formation, no one can deny that there is great similarity in their visible appearance. They are chiefly distinguished by this, that calcareous spar is often found in greenstone and basalt, but never in those lavas that have actually flowed on the surface. The lavas that have flowed in the open air have likewise a rugged aspect, hardly to be mistaken, acquired by their flowing and cooling at their external surface at the same time. A crust is formed as the lava flows along, that stops for a while, or retards the progress of the stream, till, by accumulation, it gathers force, and breaks in pieces the crust, which is tossed about, and forms vast wrinkles, as it were, in the rock. The outward part of the lava is vesicular and slaggy; the interior often more compact, and in all respects similar to basalt, greenstone, &c. The lava of Hecla cannot be distinguished from some varieties of basalt; and that of Snæfel-Jokul has the same characters. Obsidian and pumice are also found in Iceland, in circumstances that leave no doubt of their volcanic origin. These resemble in all respects the stones of the same kind found in the Lipari islands, and described by Dolomieu and Spallanzani. The volcanic origin of pumice is supported by numberless observations. Sir James Hall and Dr. James Home visited a mountain on the north side of Lipari, that had escaped the survey of Dolomieu. A mass which, at a distance, they took for common lava, on a nearer approach they found to be entirely composed of obsidian and pumice, which passed into each other. The pumice had evidently flowed along with the obsidian, and formed the upper surface of the stream, which, on examination, they found to have flowed by different mouths from the great crater. The greatest breadth of this stream was about two miles and a half, and the length of it about three. Nothing can make the volcanic origin of obsidian pumice more evident than these phenomena. It is not inferred from this that they are in every case produced by fire ; but it is made certain that fire does produce them in some instances. A very remarkable fact, of which we owe the knowledge to Sir George Mackenzie, is equally favourable to the volcanic origin of pumice. About the end of January, 1783, flames were observed rising out of the sea, about 30 miles off Cape Reikianes, the western point of the Guldbringé Syssel. Several small islands also appeared, which however, on subsequent examination, were not to be found; but a reef of sunk rocks now exists in the direction in which the flames were seen, terminating in what is called the Blind Rock, over which the sea breaks. The flames lasted several months; during which time, vast quantities of pumice and light slags were washed on shore all around the Gulf of Faxé. In the beginning of June, earthquakes shook the whole of Iceland; the flames in the sea disappeared, and a dreadful eruption commenced from Skaptaa jokul, two hundred miles distant from the place where the continuance of flame over the surface of the sea, for the space of six months, had so clearly indicated the explosion of a submarine volcano. On climbing the mountain Drapuhlid, in search of pearlstone, our travellers met with masses of wood mineralized in a manner different, we believe, from any hitherto observed. It looks like charcoal, but feels much heavier, and contains a great deal of chalcedony, intersecting it in transverse fissures. It burns without flame; and when the carbonaceous matter is consumed, the substance is little altered, and its weight scarcely diminished. The Surturbrand, another kind of fossil wood peculiar to Iceland, burns with flame ; and from some specimens of it, seems not at all mineralized. It is worked as timber; and Sir George brought with him a piece which had served for a table. Another very singular phenomenon is here described, and is peculiar to Iceland, as far as is yet known. The mountain of Akkrefell is composed of beds from 10 to 20, nay sometimes 40 feet thick, consisting of amygdaloid, tuffa, all apparently in their original position, and in one that does not at all indicate the action of volcanic fire. Our geologists, therefore, were very much surprised when they found the under sides of many of these beds having a slaggy appearance, and bearing unequivocal marks of no slight operation of fire. This was the case at the under side of every bed, excepting those of tuffa, as far as they ascended. They observed also a vein of greemstone, about four feet thick, cutting these beds, and having a vitreous coating on its sides, as is usual in all the veins of the country. There are similar appearances observed in some other of the Icelandic mountains; and the slag above described is sometimes united to calcareous spar. This last circumstance is certainly a proof, that the heat which produced the slag-like appearance was applied under great pressure, otherwise the calcareous spar would have been reduced to quicklime. The face of Akkrefell, where these appearances are observed, may have been the wall or side of some volcano at the bottom of the ocean : the under sides, or edges, of the beds of greenstone may have been melted, without the beds themselves having flowed. Another of the facts brought out in this tour, will, we are persuaded, appear no less new than the preceding. Sir George was soon led to distinguish two very distinct formations of lava; the one the common ; the other, which he has distinguished by the name of Cavernous Lava, had no appearance of having flowed, but rather of having been melted in its place ; for it appears heaved up into large bubbles, or blisters, of various forms, from a few feet to 40 or 50 in diameter. Many of them had burst, and displayed caverns of considerable depth. It was on this account the name of Cavernous Lava was given them. This lava was traced to a great distance; it appeared to form large valleys; it was often covered by more recent lava–sometimes with sand, and very commonly with soil. The whole of the great plain below Hecla is composed of cavernous lava. It reaches from Cape Reikianes to Thingvalla, a distance of 55 nautical miles. The theory which Sir George has formed of the formation of this extraordinary rock, is, that it is one which has been softened, and even melted, by subterraneous heat, over a vast extent of surface, but without being removed from its place. This must have happened at the bottom of the sea, which is confirmed by the sand and sometimes gravel which cover it. But till volcanic countries are more carefully examined, we cannot hope for any stable theory of these singular phenomena. Thus we have three very curious and new facts in geology brought to light by these travels. The existence of carbonized wood, containing veins of chalcedony; the slaggy beds of amygdaloid, &c. on the face of Akkrefell; and, lastly, the cavernous lava. Sir George Mackenzie, and the two gentlemen who accompanied him, entered on the examination of a volcanic country with particular advantages, in consequence of having studied the class of rocks that have the greatest affinity to lava in the great variety of these afforded by Scotland, and particularly by the country round Edinburgh: we mean the trap or whinstone rocks, so apt to be confounded with lava, and which, in a country where the two are so much intermixed as in Iceland, would unavoidably be so, if the language which nature speaks had not been previously studied in one of its simplest forms. The volume concludes with a catalogue of Icelandic minerals, of which Sir George has presented very rich collections both to the Royal Society and to the University of Edinburgh. To all this an account of the Botany and Zoology of Iceland is added by Mr. Bright. A Meteorological Journal for the year 1811, is also given; from which, if we had leisure to enlarge on it, many curious conclusions might be deduced.
FROM THE UNIVER's A. L. MAGAZINE,
Poems on Miscellaneous Subjects. By Miss R. H.
THOUGH there is evidently much deficiency in the harmony of these pieces, they display strong indications of poetic genius, and a degree of natural painting—which (as we are given to understand, the author is very young) may possibly, when matured by time, produce a still richer colouring. In Spring, a fragment, written at Brighton, in 1808, the following lines occur:
Th' Almighty's self has cloath'd these verdant meadows,
SPIRIT OF MAGAZINES.
FOR THE SELECT Rev 1 Ews.
... [The following interesting extract of a letter, is from a very respectable gentleman in the Island of Barbadoes, to the Reverend Dr. B–, of Baltimore. We return our thanks to our friend, who has obligingly transmitted it to us for publication.] Ed. Select Reviews.
Barbadoes, 16th May, 1812.
— FOR news, we have none, politically speaking; but if I had the elegant pen of a Pliny, I should have much to say to my Tacitus—I should have to relate the appearance of a stupendous meteor, that simultaneously enlightened your entire native land, from one end to the other, on the evening of the 20th March. It seemed rapidly to pass from the south-east quarter of the heavens to the north-west, bursting in the air with the explosion of a cannon, which was heard more distinctly in the leeward part of the island. Some of those who saw it were suddenly alarmed with the appearance round them of a strong blaze of light, like the reflection of a building on fire close at hand; but on looking upward, they perceived a large globe trailing with a cone of fire that filled the whole vault of heaven with its vivid lustre: many were sensible of its heat, and all who beheld it completely by being at their doors or without, were filled with dismay. They computed its duration at two minutes, and it is generally believed to have been little less. In Christ Church and St. Philips, and indeed in every part of the island its appearance was equally awful and impressive. It was between 7 and 8 o'clock. Feeling poorly, I had retired after business to a hammock; my windows being closed, I saw not the glorious visitant.
In the bundle of our Mercury, long waiting for an opportunity, which I now hand you through Dr. M. you will find the account of the dreadful and destructive earthquake at the Caraccas, on Holy Thursday. Awful indeed are the signs of the times. But now I want the concise pen of a Pliny, to paint to you the hor