snow. My active guide was as little acquainted with the road to the top of it as I was. Our ascent from the glacier began at the foot of the mountain on the north-east, at the height of 4500 feet above the sea. About 750 feet higher up, all water had disappeared, and the depth of the snow increased, although the heat in the sun was 29° R. The lowest point, therefore, above which snow never melts here, may be considered as about 5250 feet over the level of the sea. The steepness of the mountain made the ascent now pretty difficult: the rents in the ice, too, were deeper and broader than down on the glacier, and they were sometimes covered by snow. It became, therefore, dangerous to pass over them. You have often but a slippery footstep between you and death, and your first false step is your last in the world. From caution against such danger, we walked with a rope about our waist, and, trusting to this, we courageously crossed on a bridge of snow ten feet over. The difficulty of climbing was increased, by the inconceivable, and almost intolerable, heat of the sun, which, added to the thinness of the air, produced an uncommon weakness, and a pulse nearly doubled. We recovered our strength, however, in as short a time as we lost it, and it was not long before the naked summit was reached.

With some degree of alarm we climbed up its 150 feet high loose black head, that seemed to move under us: the top of this we reached at half past eleven A. M., on the 13th July. From a mean of six observations, which corresponded with those of Engineer Major Wetlessen, in Bergen, Dean Hertzbergen, in Hardanger, and Professor Esmark, in Christiania, and from. calculations made according to the formula of La Place, the southern top of Lodal's Mantle is 6113 feet above the level of the sea. It divides itself into three elevations, the summits of which and the steepest side are naked. The rest of the mountain to the bottom is covered with an everlasting and unbroken mantle of ice and snow. By other observations, we found, that the eastern and highest top was 6408 feet above the sea. Several circum-meridian observations of the sun gave the latitude 61° 57′, though, from an accidental injury which happened to the sextant, this determination is less to be depended on.

The surface of a small stone we found on the top of the moun

tain was, in different places, covered with two sorts of lichen, L. geographicus and another. A bear, whose gloomy disposition must have conducted it to these solitudes, had left its traces on the snow which had fallen within two days, and the laugh-resembling voice of a single ptarmigan was heard. With these exceptions, organic life and vegetation had disappeared, and eternal winter had taken up its abode all around. From the summit was seen an ocean of snow, of several thousand geographic square miles extent, the waves of which seemed as if they had been instantaneously fixed, and over which single mountaintops here and there raised their white heads, which in the valleys were hid in the clouds. Skatolstop in Lyster, Tunderdalskirk towards Lomb, and Vangsen in Justedal, were the most remarkable. All was the stillness and desolation of death, which. irresistibly filled the soul with melancholy, mingled with a powerful impression of the greatness of Nature,

The author here mentions, that, on two places in the glacier, they saw a little red snow: after which, he takes a survey of the adjoining region in all directions, in which he traces by name twenty-five distinct valleys, which, to a great extent, had been filled with layer upon layer of ice from this immense mountain. He then proceeds:—Our descent from Lodal's Mantle, after they had got past the naked rocks, was quick and easy, and, after having sojourned for nineteen hours in the regions of ice and snow, we returned to Stordal with weakened eyes, and with swollen faces and lips:

The river of Justedal has its source from the glacier of Lodal, in the upper and north-west end of Lodal. After running the whole length of Justedal, it falls into a small arm of Lysterfiord, near the farm of Rödnei. Many small rivers from the other glaciers of Justedal, and the adjoining mountains, unite with it, the most of which have fallen into it before it reaches Elvekrogen. It brings down with it great quantities of sand and mica, which are found chiefly on its banks near its source. Its waters have a greyish muddy appearance, by which rivers which come from

This is one of those remarkable mountains called the Young Harlots. Its height is ascertained to be 6975 feet above the sea. It is south-east from Lysterfiord, and is seen very far off.

glaciers may be always easily distinguished. From the difference in the quantity of water furnished to it at different seasons of the year by the rain, and the melting of the shows on the mountains and glaciers, the width of its bed and its rapidity are continually varying, Sometimes in the course of two days it has changed its bed: in its course it exhibits many beautiful cascades. Often it sweeps before it beautiful holms, covered with trees and shrubs, overwhelming at the same time the adjoining corn-fields. In 1814, a flood in the river carried off large pieces of the meadows on its banks, rising so high, that the sand was found on the top-leaves of the trees. At Elvekrog it rose from 16 to 20 feet above its usual surface. As it descends from the icy regions in which it rises, its temperature becomes less frigid, till it reach Lyster, where the multitude of fruitful apple and cherry trees, the quantities of asparagus, &c. bespeak ca warmer climate than could be there expected.

On a warm dry day, July 10, of which the mean temperature was 19.7 R., the minimum depth of Justedal river opposite to the church was 6 feet in the morning; its maximum depth in the evening was about 8. Such was the difference occasioned by the melting of the snow. The velocity of the current was at the rate of 8 feet in the second, when the river was at its minimum depth, and 9 when at its maximum. Taking the mean breadth of the river, and its slope from the sides to the middle, by simple calculation, we may form an approximation to the quantity of ice and snow melted by the heat of such a day. By this calculation it will be found, that a quantity of about 31,132 cubic fathoms of water is thus added to the river every hour. Assuming, then, that the snow has fourteen times. less density than the water which comes from it, with other proper allowances, the result will be, that the quantity of snow melted into this river during half a summer's day, will amount to 5,230,176 cubic fathoms, which I have no doubt is less than the reality.

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Observations on Serpentine and Diallage Rocks. By Dr A. BOUE. In a Letter to Professor JAMESON. Communicated by the Author.

THE geological relations of serpentine are still but imperfectly known; for it is not many years since we were assured of the existence of transition serpentines in the form of short beds, or large masses in the veins, or bed-like veins, of the greenstone (diabase) of the Pyrenees (St Pé, and Valley of Baretons); in the grey wacke of Girvan and Ballantrae in Scotland (Jameson), and of Bastberg in the Hartz; in the transition slates of the northern Fichtelgebirge, and of the Vosges; in the transition limestone of Willendorf in Austria; in the Carpatho-Appenine sandstone of Waidhofen in Lower Austria, of Monte Ferrato, near Prato, Impruneta, Creboli, &c. in Tuscany, and of Borghetta in Liguria. Veins of serpentine have been detected by the geologists of Scotland, in the old red sandstone of Forfarshire.

Some of these masses present characters illustrative of an igoneous and violent origin, and throw light on the true situation and formation of other serpentines, whose contact with neighbouring rocks either has been but imperfectly seen, or not seen at all. The serpentine of Willendorf is a fine example of the injection of this rock amongst older strata. It is situated about half a mile to the west of that village, and on the right hand side of the road leading to Granbach. The limestone hills are bordered by reddish precipices, in the midst of which, the geognost sees with astonishment a thick columnar mass of serpentine rising through the limestone, to the height of 100 feet, and fairly terminating in the surrounding limestone rock. This mass is 60 feet broad below, 40 feet broad at top, has an undu lating contour, and a blackish knotted surface, as if composed of irregular spherical bodies. Small veins of asbestus and calca reous spar are contained in it, but no distinct diallage rock. It is intimately united with the transition magnesian limestone which it intersects; and between the two rocks there is a breccia composed of a mixture of the limestone and serpentine. Even the limestone itself is impregnated with serpentine matter. All the neighbouring rocks are more or less vesicular, and deeply

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coloured with red oxide of iron, so that they present to the eye a very singular and sterile aspect. The marly or argillaceous inclined strata at their base, are partly violet and reddish, and contain small veins of micaceous iron ores. In short, this locality of serpentine may be considered as illustrating the elevation of that rock from below, in the same manner as porphyry and the accompanying breccia intimate the violence of the action.

The position of the serpentine of Tuscany has already been ably described by Brongniart, although not in a complete manner, as that distinguished observer has omitted to notice several accompanying interesting phenomena. For instance, in the Valley of Garignola, the serpentine and diallage rock or euphotide, not only cover a part of the limestones and marls, which are converted into reddish jaspideous rocks; but they rise through them, and extend over them on all sides, so that they have the shape of a wedge-shaped bed, or that of a mushroom. The breccia formed of limestone and diallage rock, which Brongniart places above the jasper, does not occur every where; but only in those places where diallage rock comes in contact with broken and bruised marls and marly limestone. The limestone is then sometimes changed into a granular mass. In Austria, about one hour's walk from Waidhofen, on the northern side of the Ips, there is a hill of serpentine apparently resting upon the same marly sandstones and marls as occur in Tuscany; and not far from it, there are in those slates which contain fossil ferns, beds of bituminous and slate coal, which are regularly worked. The lowest part of this deposite probably belongs to the independent coal formation.

If our acquaintance with these more recent serpentines be increasing, geologists have not yet fixed the age of the serpentines placed amongst slaty crystalline or primitive rocks. In this class, are generally enumerated the following masses :-the serpentines of Shetland (Jameson), and of the North Cape (Buch); the bed-like veins of Portsoy (Jameson), and of the Lizard Point in Cornwall; the great zone of serpentine of the departments of Arveiron, Lot, Correze, and Upper Vienne; the hil locks of serpentine and diallage rock in the talc slate of western Liguria, and of the base of the Piedmontese Alps; of the Alps in the department of the High Alps (Brainçon, Villard, St