« PreviousContinue »
fossils. Such beds exist only where no clayslate separates the sandstone from the limestone. Near Buda Chapel, a bed of sandstone is found between a bed of limestone and of granite; and on Osmundsberg (Osmundsmountain), a bed of clayslate joins them, containing graptolithes (a small kind of orthoceratites). It is curious that this mountain, where at least three beds of different rocks occur, is the richest in fossils of the whole province, and the uppermost bed contains, besides the common entomostracites, a great number of anomites, turbinites, and madrepora stellaris, with several remains resembling corals. Entomostracites, crassicauda, * and laticauda, + are peculiar to this mountain. The limestone is commonly red, like that from Gothland: now and then it becomes white: it then has no fossils, and sometimes contains galena. It is curious that no alumslate or swinestone (anthracolite, Werner), is found in this province accompanying the limestone, which, in other places, is generally the case.
The island of Gothland agrees with respect to the limestone and its fossils so completely with the Osmundsberg, that it must follow next. Gothland is by far the largest of all beds in Sweden, which contain petrifactions, so that it has almost as large a surface as all the rest together; which seems to be again in direct proportion to the greater basin in which it was formed, which is the Baltic. The transition formation is perfectly isolated, the nearest rocks of granite being at a distance of about fifty miles. It is, however, probable, that it rests on a flat plain of granite, partly covered by this formation, and partly by the sea, which is no where round the island of
considera ble depth. The beds of limestone are perfectly horizontal, except at Thorsborg. Upon what kind of rock the limestone immediately rests is not known, except in one place in the west part of the island, where below it a calcareous sandstone has been observed, containing the same mytilites, as the Osmundsberg; and this proves still more the similarity between these two parts of the transition formation, so far distant from each other. No clayslate has been found in Gothland. The limestone is light grey, compact, and does not contain any fossils, except on the faces where two beds join ; they are a kind of imperfect fossil, which resembles a phacites; and which is peculiar to Gothland. On the faces of the upper beds occur a quantity of unusually large encrinites, anomites, and millepora; and upon the uppermost face, a great number of corals, turbi
* Entomostracites crassicauda Wahlenb. “ oculis ad angulos superiores capitis convexi, cauda subtriangulari; marginibus involutis crassissimis.” It is very rare to find complete specimens ; but different parts, principally the tail, have been found frequently.
+ Entomostracites laticauda Wahlenb.: oculis ad latus capitis convexissimis, cauda suborbiculari; limbo latissimo planissirno radiato integerrimo. It is always twice as large as the former; and it is, therefore, not improbable, that it is a fossil of an older animal of the same kind. It has not yet been found entire, but only head and tail, and never in any other rock than greyish-white limestone.
nites, &c. which might only be expected in the largest system of Swedish transition rocks, that had been formed in the sea itself.
The island of Oeland consists likewise only of transition rocks, no granite or gneiss having been formed there. The limestone is at the utmost 140 feet thick ; it covers the whole island, except a few places on the west side, where other rocks are seen, that lie under the limestone, viz. lowermost near Aleklinta, a sandstone very compact and free from lime; then follows a bituminous shale with subordinate beds of swinestone without fossils. These beds of shale are, when compared with those of the other systems, very imperfect, except in one place, where they increase in thickness, change into alumslate with the usual small entomostracitæ* in the beds of swinestone, and with small anomites lenticularis.† The limestone is usually red, and contains many orthoceratites, and the common ento mostracites expansus ; # with these exceptions it is quite free from the remains of marine animals.
The system of Westgothland is one of the inost interesting on account of the nature of the rocks which compose it, and the external appearance of the country which it forms. The large plain of Westgothland is formed of common gneiss, which, in many places, rises into small hills, never high above the level of the lake Wineren, and disappearing near the hills of transition rocks; so that it seems as if these had been deposited upon a perfect plain. The gneiss likewise near the rocks of the transition formation is somewhat different, principally on the east part of the plain; it contains green earth, instead of mica, and its feldspar weathers very readily; such is the rock at Lugnaes. The rocks belonging to this system are, (beginning at the lowermost), sandstone, which rests upon the gneiss, and which in the east part of this district is first met with at a height of 318 feet above the level of the sea ; its thickness amounts to 77 feet, and it contains no fossils. Upon this follows the alumslate, the lowermost beds being the purest; the upper ones are often only a bituminous slate; together about 78 feet thick. The next layer is limestone, 202 feet thick ; it does not contain beds of other rocks; but the limestone itself varies in colour, hardness, and the fossils which it contains : the lower part is white, semicrystalline, and contains only echinosphaerites pomum. The next is grey; it contains large entomostracites and few orthoceratites ; the uppermost is mostly red, and contains a great number of large orthoceratites. Upon the limestone follows a bed of clayslate, 122 feet thick, of which the lowermost part is like the bituminous slate of the bed below the limestone; so that it is frequently necessary to distinguish them by their fossils, of which a small kind of orthoceratites is peculiar to the bituminous slate above the limestone. Next follows a chertlike liver-coloured
* Entomostracites gibbosus.--Cæcus, capite antice truncato planiusculo fronte oblonga, jugoque dorsali gibboso, cauda triangulari utrinque bidentata. Wahlenb. Entomol, paradoxus ß cantharidum Linn. Syst. Nat.
Entomostracites scarabæoides. - Cæcus, capite hemisphærico antice rotundato, fronte subovato antrorsum angustiore, cauda utrinque sinuato-tridentato. Wahlenb.
Entomostracites pisiformis.-Cæcus hemisphæricus marginatus ; fronte teretiuscula. Wahlenb. Entomolithus paradoxus y pisiformis Linn. Syst. Naturæ.
t Anomites lenticularis.-Clausus (nullo foramine nec hiatu) suborbicularis utrinque convexicus oculus radiatim undulatus.
# Entomostracites expansus : oculis frontalibus, capitali testa antrorsum semiorbicu. lari plana laevi; caudali magnitudinem capitis, &c. Wahlenb. Entomolith. paradoxus et expansus. Linn. Syst. Nat. Trilobites disitatus, Brunnich ; T. novus. Schlottheim.
a kind of stone which now and then forms beds of the thickness of a foot, and contains echinosphaerites aurantium; uppermost lies a whitish stone resembling sandstone. Upon these beds of slate rests a large bed of greenstone; it weathers readily, and and falls to sandy grains; on this account the people call it sandstone. It is often divided into four-sided columns perpendicular to the stratum upon which it rests.
These rocks, of which the transition formation of Westgothland is formed, occur in three places completely separated from each other; and it is highly probable that no connexion ever existed between them, because the relative thickness of these strata is different, and not a trace of transition rocks is seen between them, while it rises on these three hills to a very considerable height. The first and largest mass of transition rocks occurs near
Falkjoping, where a large plain of sandstone extends from the sources of the river Lidaa to the mouth of the river Tidaa over nearly 30 miles. Upon this plain rest three similar plains of limestone, separated from each other by narrow valleys, and each of them containing two or three summits of trap. The first of these limestone plains called Storfalan (the large common), is remarkable for its fertility ; it has two summits of trap, the Mosseberg and Aalleberg; the second limestone plain is Taaredalsberg ; and the third, Billingen, almost entirely covered by the bed of trap. The alternation of hard and soft stone in these mountains, occasions the formation of terraces in all of them, and the whole trap family has received its name from the stair-like appearance of these hills ; trapp in Swedish signifying stair.
Kinnekulle, a hill on the south side of the lake Weneren, consists of the same rocks, but the limestone is only 150 feet thick, and the summit of clayslate and trap rises 470 feet above the limestone; but it is impossible to ascertain how thick each of these two strata is. The whole thickness of the horizontal beds at the Kinnekulle is 730 feet. Halle and Kenneberg are two other hills of transition rocks at the mouth of the Gothaelf, near Wenersberg. The clayslate and alumslate are each only about 50 feet thick ; the limestone seems to be altogether wanting, and the trap on the Hunneberg is 128 feet; on the Hal eberg 166 feet thick. Peculiar to Westgothland are: entomostracites paradoxissimus, the largest of the whole tribe, whieh, according to some detached parts, must sometimes have been about a foot in length, entire specimens of that size have, however, never been found ; Entomostracites bucephalus, of which the head only has been found, but which seems hardly to have been inferior in size to the preceding. These occur in the alumslate, which, in this system, is more perfect than in any other ; but besides these and the common small entomostracitæ and anomites lenticularis, no fossils have been found in this slate. The limestone contains the large orthoceratites, the common entomostracitæ, and echinosphaerites pomum; all coralline petrifications, and all anomiæ, are wanting, but these again occur in the sandstone-like slate immediately below the greenstone, at a height of about 800 feet above the sea. It is extremely remarkable that these fossils are only found in the uppermost beds; in Westgothland in this clayslate, in the island of Gothland in the
uppermost bed of limestone.
The transition formation in Oestergothland is low, mostly covered with gravel and earth, and no interesting fact has been observed respecting it; the same is the case with that of Nerike; and in Upland, only a number of loose blocks have been found, but no transition rock in situ.
In Scaane, the southernmost province of Sweden, and on two sides bordered by the sea, this formation is of great extent, but 80 scattered and so much covered by beds of gravel and sand, that the connexion of its different parts is not readily discoverable. In the south part, a long ridge of hills appears; the rock .
; is white, and consists of granular quartz; it is in fact a quartz
; rock; mica, however, is rather rare in it. At Gladson, near Cimbrisham, it contains veins of fluor and galena, the fluor being frequently crystallized in regular octahedrons, a form which is rather rare. Limestone, alumslate, bituminous slate, and clayslate, occur in many places; even greywacke and perpendicular veins of greenstone, often several miles in length, and not seldom twenty or thirty fathoms in width, occur frequently. When the slate is weathered, there remain ridges of steep barren hills, which rise to 50 or 60 feet above the surrounding fertile country. No fossils are peculiar to this system of the transition formation, except entomostracites spinulosus,* of which entire specimens have been found only in Scaane, though in Westgothland fragments of the same animal occur. The alum.. slate has been worked at Andrarum for more than a century to supply an alum manufactory, and at a depth of 400 feet, they had not yet passed through it.
* Entomostracites spinulosus.-Cæcus, capite late semilunari, angulis posticis spinulosis, fronte oblonga convexissima, cauda rotundata spinulis trunci postremis breviore.
On the Presence of Muriatic Acid in the Air of the Atmosphere.
From several papers by Hermstadt, Vogel, Pfaff, &c. The Dutch chemists appear to have satisfactorily ascertained the presence of muriatic acid in atmospheric air under certain circumstances, and the same fact seems to have been discovered a second time within the last two or three years.
M. Hermstadt, of Berlin, in a treatise on the sea-baths of Doberan on the coast of Mecklenburgh, first adverted to some properties which seemed peculiar to the air collected over the sea, or in its neighbourhood; the most remarkable circumstance was, that water shaken with it, precipitated nitrate of silver ; he did not state his opinion that this was occasioned by muriatic acid, but left it undecided. Upon the suggestion of M. Vogel, of Munich, while on a visit to M. Kruger, of Doberan, the latter made some experiments which proved that water distilled from solutions of most earthy and even metallic muriates, contains some muriatic acid. The experiments were the following:
An ounce of muriate of potash was put into a distilling apparatus with 30 ounces of distilled water; the solution was kept slowly boiling, and 10 ounces of water were condensed; three drops of a concentrated solution of nitromuriate of platina were added to three ounces of this water, and the solution was evaporated in a glass vessel until only about five drops remained. On cooling, a reddish yellow sediment was deposited, which was difficultly soluble in water.
Solution of nitrate of lead, when mixed with the water, instantly produced turbidness.
Solution of nitrate of silver produced a similar effect, but more readily.
Litmus paper was not changed by the water.
This experiment was repeated, excepting that muriate of magnesia was used instead of muriate of potash. When the distilled water was heated in a silver vessel, and a few drops of solution of carbonate of soda added to it, every drop produced turbidness, which instantly disappeared. When eight ounces of the distilled water were evaporated with some carbonate of soda until half an ounce remained, a small quantity of a white precipitate appeared, which, when sufficiently washed, dissolved in sulphuric acid with effervescence.
Solution of nitrate of silver rendered the distilled water turbid, and nitrate of lead much more so. Litmus paper remained unchanged.
When the experiment was repeated with muriate of soda, the