Among the most remarkable traits in his character, were his incorruptible regard for every thing that he believed to be true, honourable, and good,-his pure love of science, with no reference whatever to any selfish, ambitious, and avaricious feeling, his rare modesty, undebased by the slightest vainglory or boasting. He was benevolently disposed towards all men, and seldom or never was a slighting or contemptuous word respecting any individual heard to fall from him. When he was forced to blame, he did it briefly, and without bitterness; for his blame had always respect to actions, and not to persons. His friends as well as his relations, feel severely his loss; for every person to whom he had once given his confidence, might depend upon the unchangeableness of it. His friendship was never the result, like that of so many other persons, of any selfish calculation, but was always founded on a favourable opinion of the personal worth of the man. Amidst all the unpleasant accidents of his life, and of these there was no want, he shewed an invincible placidity, founded, not on any want of lively feeling, but in the firmness of his resolution. In his common behaviour, he was always pleasant and composed, and very far from being disinclined to a joke. To all these virtues, the chief ornament was added by his true religious feeling; and I believe I am not saying too much, when I aver that he was a model of the true meaning of that epithet, which is so frequently misunderstood. His religion consisted not in words and forms, in devotion to the system of any party,in a general assent to any thing external, or to any thing artificially constructed,-not in positive doctrines, nor in any ecclesiastical observances, which, however, he considered to be necessary and honourable, but in a zealous and conscientious discharge of all his duties,-not only of those which are imposed by the laws of men, but of those holy duties of love and charity, which no law of man, but only that of God, can command, and without which the most enlightened of men is but "sounding brass and a tinkling cymbal." He early shewed this religious feeling, by the beforementioned great and honourable care which he bestowed in educating the children of those to whom he was bound by no external interest, and by no human law. Nor did he shew less care, at an after period, towards the assistants and apprentices of his office, to whom he refused no instruction, and in whose success he took the most active concern. He shewed his religious feeling still farther by the very strict conscientiousness with which, as the possessor

of an office, he laboured for the best condition even of such things as did not fall under views of policy. He shewed it, in the last place, by the pleasure which he took in every thing that was good and excellent, and by the ready interest which he felt in every undertaking which he believed to be of general utility. In fine, he was a man equally removed from the superstition and infidelity of his age, who carried the holy and eternal principles of religion not on his lips, but in the inmost feelings of his heart, from whence they emanated in actions which pervaded and enobled his whole being and conduct.

ART. II.-On Rock Formations. By Baron ALEXANDER HUMBOLDT.*

THE word formation designates, in Geognosy, either the manner in which a rock has been produced, or an assemblage of mineral masses, which are so connected together, that they are supposed to have been formed at the same period, and present, in the most distant parts of the world, the same general relations of situation and position. It is thus that the formation of obsidian and basalt is attributed to subterranean fires; and thus also that we say the formation of transition clay-slate contains lydian-stone, chiastolite, alumslate, and alternating beds of black limestone and porphyry. The first acceptation of the word is better adapted to the genius of the language; but it has relation to the origin of things, to an uncertain science founded upon geogonic hypothesis. The second acceptation, now generally adopted by the French mineralogists, has been borrowed from the celebrated school of Werner: it indicates what is, not what is supposed to have been.

In the geognostical description of the globe, we may distinguish different degrees of aggregation of mineral substances, simple or compound, according as we rise to more general ideas. Rocks which alternate with one another, which are usually associated, and which present the same relations of position, constitute a formation; the union of several forma

* Translated from Essai Géognostique par Alexandre de Humboldt.

tions constitutes a district or terrain; but these different terms of rocks, Formation and Terrain, are employed as synony mous in many works of geognosy.

The diversity of the rocks, and the relative disposition of the beds which form the oxidised crust of the earth, have, from the most remote times, fixed the attention of men.. Wherever the working of a mine was directed upon a deposit of salt, of coal, or of clay-iron, which was covered with a great number of beds of different natures, it gave rise to ideas more or less precise regarding the system of rocks pe culiar to a district of small extent. Furnished with these local details, and full of prejudices which arise from custom, the miners of a country would disperse themselves over the neighbouring districts. They would do what geognosts have often done in our days; they would judge of the position of rocks of whose nature they were ignorant, according to imperfect analogies, according to the circumscribed ideas which they had acquired in their native country. This error must have had a fatal influence upon the success of their new researches. In place of examining the connection of two contiguous dictricts, by following some generally extended bed,-in place of enlarging and extending, so to speak, the first type of formations which had remained impressed upon their minds, they would be persuaded that each portion of the globe had an entirely different geological constitution. This very old popular opinion has been adopted and supported, in different countries, by very distinguished men; but since geognosy has been elevated to the rank of a science, the art of interrogating nature brought to perfection, and journeys made into distant countries, have presented a more exact comparison of different districts, great and immutable laws have been discovered in the structure of the globe, and in the superposition of rocks. Since, then, the most striking analogies of situation, of composition, and of organic bodies contained in contemporaneous beds, have manifested themselves in the two worlds, in proportion as we become accustomed to consider the formations under a more general point of view, even their identity becomes every day more probable.

In fact, on examining the solid mass of our planet, we perceive that some of those substances with which oryctognosy (descriptive mineralogy), makes us acquainted in their individual capacities, are met with in constant associations, and that these associations, which are designed by the name of Compound Rocks, do not vary like organic beings, accord

ing to the differences of the latitudes, or of the isothermal lines in which they occur. The geognosts who have travelled over the most remote countries, have not only met in the two hemispheres with the same simple substances, quartz, felspar, mica, garnet or hornblende; but they have also found that the great mountain masses present almost every where the same rocks, that is to say, the same assemblages of mica, quartz, and felspar in the granite; of mica, quartz, and garnets in the mica-slate; of felspar and hornblende in the syenite. If it has sometimes been thought at first that a rock belonged exclusively to a single portion of the globe, it has been constantly found by later rescarches, in regions the most remote from its first locality. We are tempted to admit. that the formation of rocks has been independent of the diversity of climates; that perhaps it has even been anterior to them, (Humboldt, Geographie des Plantes, 1807, p. 115; Vues des Cordilleres, vol. i. p. 122). Rocks are found to be identical where organic beings have undergone the most varied modifications.

But this identity of composition, this analogy which is observed in the association of certain simple mineral substances, might be independent of the analogy of relative situation and of superposition. One may have brought from the islands of the Pacific Ocean, or from the Cordilleras of the Andes, the same rocks which are observed in Europe, without his being permitted to conclude that these rocks are superimposed in the same manner, and that after the discovery of one of them it might be predicted with some degree of certainty what are the other rocks which occur in the same places. It is to discover these analogies of situation aud relative position, that the labours of geognosts should tend, who delight to investigate the laws of inorganic nature. In the following tables, we have attempted to unite all that is known with certainty, regarding the superposition of rocks in the two Continents, to the north and south of the Equator. These types of forma tions will not only be extended, but also variously modified, in proportion as the number of travellers qualified to make geognostical observations shall become increased, and as complete monographs of different districts at great distances from each other shall furnish more precise results.

The exposition of the laws observed in the superposition of rocks, forms the most solid part of the science of geognosy. It must not be denied, that the observations of geognostical situation often present great difficulties, when the point of contact of two neighbouring formations cannot be reached,

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or when they do not present a regular stratification, or when their relative situation is not uniform, that is to say, when the strata of the upper deposits are not parallel to the strata of 'the lower. But these difficulties (and this is one of the great advantages of observations which embrace a considerable part of our planet), diminish in number, or disappear entirely, on comparing several districts of great extent. The superposition and relative age of rocks, are facts susceptible of being established immediately, like the structure of the organs of a vegetable, like the proportions of elements in chemical analysis, or like the elevation of a mountain above the level of the sea. True geognosy makes known the outer crust of the globe, such as it exists at the present day. It is a science as capable of certainty as any of the physical descriptive sciences can be. On the other hand, all that relates to the ancient state of our planet, to those fluids which, it is said, held all the mineral substances in a state of revolution, to those seas which we have raised to the summit of the Cordilleras, to make them again disappear, is as uncertain as are the formation of the atmosphere of planets, the migrations of vegetables, and the origin of different varieties of our species. Yet the period is not very remote when geologists occupied themselves by preference with the solution of these almost impossible problems, with those fabulous times of the physical history of our planet.

In order to render the principles better understood, according to which the following table of the superposition of rocks is constructed, it becomes necessary to premise observations furnished by the practical examination of different districts. We shall begin with remarking, that it is not easy to circumscribe the limits of a formation. The Jura limestone and the Alpine limestone, which are separated to a great distance in one country, sometimes appear closely connected in another. What announces the independence of a formation, as has been very justly observed by M. de Buch, is its immediate superposition upon rocks of a different nature, and which consequently ought to be considered as more ancient. The red sandstone is an independent formation, because it is superimposed indifferently upon black (transition) limestone, upon mica-slate, or upon primitive granites; but in a country where the great formation of syenite and porphyry predominates, these two rocks constantly alternate. There results that the syenite rock is dependent upon the porphyry, and scarcely any where covers by itself the transition clay-slate or primitive gneiss. The independence of formations does not, be