and admire the curious domes of snow over head; these are caused by the hot steam melting the snow over it. Some of these excavations are very spacious, resembling vaulted roofs of marble; and the snow, as it melts, falls in showers, like heavy rain, to the stream which appears to owe its origin in a great measure to these supplies. Having only a short-scaled thermometer with me, I could not ascertain the precise heat of the spring, but it was too hot to keep the finger in it for more than two seconds, and must be near the boiling point. Rice boiled in it but imperfectly. The range of springs is very extensive, but I could not visit them all, as the rest are in dark recesses and snow caverns. The water of them rises up with great ebullition through crevices of the granite rock, and deposits a ferruginous sediment, of which I collected some. It is tasteless, and I did not perceive any peculiar smell. Hot springs are frequent in the Himalaya: perhaps they may be a provision of nature, to ensure a supply of water to the heads of the rivers in the winter season, when the sun can have little or no power of melting the snows in those deep defiles.

"From near this place, the line of the course of the Jumna is perceptible downward to near Lakha Mandal, and is 55° 40' S.W. From the place called Bhairo Ghátí, the bed of the river is overlaid with snow to the depth of from 15 to 40 feet, except at one or two places, where it shews itself through deep holes in the snow.

"The snow bed is bounded to the right and left by mural precipices of light coloured granite. On some ledges there is a sprinkling of soil, where the B'hojpatra bushes grow. The end of this dell or defile is closed, as before observed, by part of the base of the great snowy mountain of Jumnotri, and which is visible from the plains. The altitude of the part of the mountain, visible, is 29° 48′; but higher parts are concealed by the lower and nearer. The face of the mountain, which is visible to the height of about 4000 feet, is entirely cased in snow and ice, and very steep. The foot of the base is distant from the hot springs about 500 yards, and immediately where the ascent becomes abrupt, a small rill is seen falling from a rock, which projects from the snow. It is about 3 feet wide, and shallow, being only a shower of spray produced by the snow now thawing

in the sun's rays at noon. Above that, no water whatever is seen. If there were any, it would be visible, as the whole steep base of the mountain is exposed to view, directly in front; consequently, the above rill is the most remote source of the Jumna. At the present season, it was not possible to go to it, as the snow-bed was further on impassable, being intersected by rents and chasms, caused by the falling in of the snow, as it melts by the steam of the boiling springs below it.

“Here, then, is the head of the Jumna, on the S.W. side of the grand Himálaya ridge, differing from the Ganges, inasmuch as that river has the upper part of its course within the Himalaya, flowing to the south of east to the north of west; and it is only from Suchi, where it pierces through the Himalaya, that it assumes a course of about south 20° West."

The fall of the Jumna, from Jumnotri to the Dún, is very considerable. The height of Jumnotri above the sea is about 10,483 feet. The latitude of the hot springs is 30° 58′ 52′′; and that of the small hill, which is the head of the Jumna, is 30° 57′ 6′′.

"Having finished my observations by two o'clock, I set out to return. The heat of the sun had then began to melt the snow on the cliffs on both sides, and many rocks and lumps of snow were falling down: this obliged us to run with all speed down the snow-bed, to get out of the way of these missiles. Several of the people had narrow escapes from the falling fragments, but no one was struck.

“The inhabitants of Cursál say, that it is seventeen years since they had so severe a winter as the last.-At Jumnotri, the inclination of the granite rock is from 43° to 45° from the horiThe apex being to the S.W. or towards the plains.

zon.

"As the season was not sufficiently advanced to allow of my passing to the Ganges by the Chiá or Cilsaum mountains, both of which are at present impassable from the depth of snow on them, I returned to Catnaur, and going up the Shiálba glen, crossed the ridge, which divides the two rivers at the Jackeni Ghat, and descended by Bauna, to Barahat, from whence I proceeded up the Ganges to Reital, and continued my route beyond Gangotri, as before mentioned."

ART. III.-On Petrifactions, or Fossil Organic Remains. By Baron ALEXANDER HUMBOLDT.

OF the various proofs of the identity of formations in the most distant regions of the globe, one of the most striking, and for which we are indebted to the assistance of zoology, is the identity of the organic bodies contained in strata having a similar geological position. The researches which lead to this kind of proofs, have exercised the skill of the learned, since Messrs De Lamarck and Defrance began to determine the fossil shells of the neighbourhood of Paris, and since Messrs Cuvier and Brongniart published their memorable works on the fossil bones and tertiary formations. As the greater portion of the formations which compose the crust of our planet contain no organic remains, and as these remains are of very rare occurrence in the transition formations, and are often broken and difficult to detach from the rock in the older secondary formations, the study of fossil organic bodies comprehends but a small part of geognosy,-a part, however, very worthy of the attention of the philosopher. The problems which present themselves in this department, are numerous: They bear relation to the geogra phy of animals, whose races are extinct, and which, for this rea son, already belong to the history of our planet: They render necessary the discussion of the zoological characters, by which we would distinguish the different formations. To remain faithful to the plan which I have proposed to myself, of only considering the various objects in the most general way, I shall now mention those questions of Geognostical Zoology, which appear the most important in the present state of science, and whose solution has been tried with more or less success. What are the Genera, and (if the state of preservation and degree of attachment to the rock permit a more complete determination) what are the Species, to which the fossil remains may be referred? Does an exact determination of the species discover any which are identical with the plants and animals of the present world? What are the classes, the orders, and families of organized beings, which present the greatest number of these analogies? In what proportion does the number of identical genera and species increase, with the newness of rocks or of earthy deposits? Is the

order observed in the superposition of transition, secondary, tertiary, and alluvial formations, every where in harmony with the increasing analogy which the types of organization present? Do these types succeed each other from below upwards, passing from the grey-wackes and black transition limestone, through the coal sandstone, Alpine limestone, Jura limestone, chalk, the tertiary gypsum, to the fresh water and modern alluvial formations, in the same order which we have adopted in our systems of natural history, by arranging animals according as their structure becomes more complicated, and as other systems of organs are added to those of nutrition? Does the distribution of fossil organic bodies indicate a progressive development of vegetable and animal life upon the globe,-a successive appearance of acotyledonous and monocotyledonous plants, of zoophytes, crustacea, mollusca; (cephalopoda, acephala, gasteropoda), of fishes; oviparous quadrupeds; of dicotyledonous plants; of marine mammifera and of terrestrial mammifera? Considering fossil organic bodies, not in their relation with such or such a rock in which they have been discovered, but simply with regard to their climacteric distribution, is an appreciable difference to be observed between the species which predominate in the old and in the new continent, in the temperate climates, and under the torrid zone, in the northern and in the southern hemisphere? Is there a certain number of tropical species which are found every where, and which seem to announce, that, independently of a distribution of climates similar to the present, they have experienced, in the first age of the world, the high temperature which the cracked crust of the globe, strongly heated in its interior, had given to the ambient atmosphere? Can the fresh-water shells be distinguished with certainty, by means of precise characters, from those of marine origin? Is the determination of the genus sufficient for this purpose, or are there not (as among fishes) certain genera, the species of which live both in the sea and in rivers? Although, in some of the tertiary rocks, the fluviatile shells occur mixed (for example, at the mouths of our rivers) with the pelagic shells, do we not observe, that the first form particular deposits, characterizing formations, the examination of which has been hitherto neglected, and which are of very recent origin? Have fresh-water shells ever been discovered under the Jura

limestone, among reputed fluviatile fishes, in the bituminous slate of the Alpine limestone? Do identical species of petrifactions or fossils occur in the same formations in different points of the globe? Are they capable of furnishing zoological characters for distinguishing the different formations? Or, should it not rather be admitted, that species which the zoologist is entitled to consider as identical, following the methods usually adopted, penetrate across several formations; that they are even seen in those which are not in immediate contact? Should not the zoological characters be taken both from the total absence of certain species, and from their relative frequency or predominance, as well as from their constant association with a certain number of other species? Is it right to divide a formation, whose unity has been determined from relations of position, and from the identity of the beds, which are equally interposed between upper and lower strata, merely because the first of these strata contain fresh-water shells, while the last contain marine ones? Is the total absence of organic bodies in certain masses of secondary and tertiary formations, a sufficient reason for considering these masses as particular formations, if other geognostical relations do not justify this separation?

Some of these problems engaged the attention of geologists at an early period. Lister had already maintained, upwards of 150 years ago, that each rock was characterized by different fossil shells,(Philosophical Trans., No. 76, p. 2283.) With the view of proving that the shells of our seas and lakes are specifically different from fossil shells (lapides sui generis), he affirms, "that the latter, for example, those of the Northamptonshire quarries, have all the characters of our murices, tellina, and trochi; but that naturalists, who are not accustomed to content themselves with a vague and general perception of things, will find the fossil shells specifically different from those of the present world." Nearly at the same period, Nicolas Stenon, (De solido intra solidum contento, 1669, p. 2, 17, 28, 63, 69, fig. 20, 25,) first distinguished "the (primitive) rocks anterior to the existence of plants and animals upon the globe, and consequently never containing organic remains, and the (secondary) rocks superimposed upon the first, and abounding with these remains (turbidi maris sedimenta sibi invicem imposita)."