oval flakes or small specks of whiteness, are really distinct and independent systems, floating at such an immeasurable distance that the light has to wander millions of years before it can break in its faintest morning-streak upon our horizon. Mark the analogy, therefore, ere you scoff at the credulity of the geologist, or the power of the rain-drop to transmit an image of itself through so many revolutions and ages of the earth's history. How impalpable a substance is light! how readily effaced its impressions, or intercepted its brilliant colorings, by the interposition of the frailest creation of matter-an insect's wing, the covering of a leaf, the disc of a flower-petal. But the light, thus easily obliterated or dimmed on earth, has been maintaining its own solitary independent course through every medium, every change, of upper and nether worlds. The moment of its efflux from remotest orb, in depth of infinite space, gave to every particle of that feebly or intensely luminous beam, a separate being and direction, with no return back to its parent source. And now, says the intelligent astronomer, as it drops gently into the searcher of his telescope, that is a ray from yon far distant unresolvable cluster of stars, or of astral systems, for millions of years traveling through these incalculable heights, when as yet the Chaldee sages had pointed no instrument to the heavens, nor the learned of Memphis recorded an observation. Can you deny to other matter, argues the geologist, a similar tenacity of self-preservation, the vitality of impress which merely records the uniformity of the laws and constitution of nature, and which intimates that, through all past time, there were showers to cheer and to refresh the products of the earth? Truth becomes more marvelous than fiction when traced in researches such as these—showing the illimitable range over time and space permitted to human inquiry-and producing, at the same time, things both of heaven and of earth scarcely to be dreamt of in human philosophy. V. But the economic and practically useful, no less than the speculative or fanciful, form constituents of the new red sandstone formation. The strata are not only indented with impressions of strange and doubtful origin; they inclose, like those of the carboniferous system, treasures of the greatest value; and nature, in ceasing to abound in one kind of product, has been no less exuberant in others, equally contributive to the comfort and convenience of man. In this class of rocks are situated our great deposits of ROCK-SALT and gypsum, of the former of which, beside supplying the demands of the home market, the mines of Cheshire alone export from Liverpool upward of half a million of tons weight. The distribution of the saline mineral is very general over the earth, and by no means constant in its geognostic position; as, for example, in Galicia, it is found among the tertiary deposits; in New York, it occupies the middle of the silurians; while in Hungary, Poland, and England, it is uniformly associated with the new red sandstone. Rock-salt has been long known to and prized by mankind; it became an object of taxation or tribute six hundred and forty years before the Christian era, as narrated of Ancus Martius, "salinarum vectigal instituit ;" and hence centuries afterward, when Great Britain was in possession of the Romans, the legions received salt as part of their pay or "salary." Our richest mines are in Cheshire, and along the districts watered by the Dee, the Weaver, and the Mersey. The beds, or rather masses, are imperfectly stratified, and vary in thickness from a few inches to 120 feet and upward: gypsum and variegated marls may be regarded as constants in the formation, the gypseous deposits sometimes attaining the enormous depth of 150 feet. We speak of the beds of gypsum as deposits, in common with those of the sandstone matrix in which they are imbedded. It appears, however, on inquiring into the theory of their origin, that they are not strictly such in the true sense of deposits-originally as gypseous deposits-but altered limestones, metamorphosed by the action of gases which have escaped from beneath, and permeated the calcareous mass. The carbonates of lime have been converted into the sulphates of lime, by means of gaseous emanations produced in unknown volcanic depths. Even the dolomitic member of the group is supposed to have a like metamorphic origin; the needful elementary agencies having entered into the parent limestone, and converted it into the magnesian type. Why nature should not have done these things directly, at the first offthrow, science could not, perhaps, very satisfactorily answer the skeptically inquiring mind; but, as the ingredients are all chemi cally well known, and more especially as there is a vast laboratory ever at work, filled with all kinds of elements, in her subterranean regions, any hypothesis of formation is as rapidly established as it is conceived, and the interest of the subject humanly speaking augmented. The celebrated Berzelius, when questioned on the point, had his ready solution of the problem, easily derived from his unparalleled stores of chemical knowledge :—“ Give me a substance containing sulphur-admit the presence of the vapors of sulphur, or sulphurous or sulph-hydrous vapors,-let limestone be also present, and water on the surface or in the atmosphere, AND WE SHALL READILY HAVE GYPSUM." The origin of the saltness of the ocean is still a mystery in science; equally involved in doubt and conjecture is that of the other member of the series, the rock-salt formation. The generally adopted theory, however, is, that it was dependent on volcanic agency for development, as it both contains, and is uniformly associated with, the acids, and other materials found in connection with volcanoes. The chlorides of sodium and gypsum, for example, are at present sublimed from volcanic vents; vapors charged with sulphuric acid are constantly issuing from the same sources; and these passing through or associated with the saline waters of the period, must have aided in the formation of rock-salt and gypsum, which occur more frequently in irregular masses than in true stratified deposits. An additional corroboration of the theory is inferred from the circumstance, that the gypsum accompanying the rock-salt is anhydrous, that is, free from water before exposure to the action of the atmosphere. Hence the conclusion, that the consolidation of both the rock-salt and the gypsum must have been effected by the agency of heat, as, by means of aqueous deposition, a hydrometric influence would have been sensibly perceived. Wonderful certainly is all this-the inclosing, the consolidation, the arrangement of these remarkable substances. The sea, in the first instance, may readily and abundantly have supplied all the elements of the formation; but how collected and retained, crystallized and incrusted, layer upon layer, over the rocky bottom and volcanic inner chambers, are points still of nice geological inquiry. The celebrated salt mines of Cracow, in Poland, are wondrous operations of the art of man, into the still more wondrous products and recesses of nature. Here the entire arrangements of a city are almost perfected; the streets, marketplace, chapel, rivers, reservoirs, grottoes, and all the requirements of comfort and safety gleaming in a blaze of saline crystals. 'Scoop'd in the briny rock long streets extend Their hoary course, and glittering domes ascend; And the bright vault returns the mingled blaze." The deposit near Cracow is worked on four different levels or stories, divided into innumerable compartments, with thousands of excavations in every direction, and descending to the vast depth of one thousand feet below the surface. The length of the several passages, in their windings and turnings, is calculated to be nearly three hundred miles; about two thousand men are constantly employed in the mining operations; and, though the operations have been carrying on for the known period at least of six hundred years, the mass of rock-salt in the locality is still of inex haustible extent. The mines in our own land are equally remarkable after their kind, and cannot fail to interest, if not to astonish, the neophyte who ventures a descent. From the mode in which they are worked, the huge pillars left to support the roof, the thousand lights that illuminate the caverns, the reverberations from the blasting which at intervals ring through their depths, a grandeur and impressiveness are imparted to a scene which scarcely any other combination of objects could produce. And another world-a world of coal and iron-in all its magnificence and riches, lies interred under these glistering stores of lime and salt! How strangely contrasting in their qualities and structure the two formations. But except that a wise and far-seeing Providence collected and garnered up the waste and decay of both for man's use, no principle have we to guide us when speculating on their mineral properties and arrangement-no natural law certainly, self-acting upon matter and evolving new creations of its own, organic or inorganic, to reveal His inscrutable purposes. CHAPTER III. THE OOLITIC OR JURASSIC SYSTEM-AGE OF REPTILES. WHEN one is about to travel, or to undertake a journey of any distance from the daily beat of home, it is very seldom indeed that he puts into his pocket a book of science. Voyages, travels, a review at most, or the newest novel, may fill up a spare place in the portmanteau: anything that requires study, or would draw upon the reflective faculties, can be no fitting companion for the occasion, with at least nine-tenths of our moving public. If the preceding pages have been perused with any attention at all, it is to be hoped that other things will be considered as worthy of a passing glance, as sure we are they cannot fail to be replete with lessons of instructive wisdom. On the ground of mere ephemeral curiosities by the way, geological matters claim consideration. They are exhaustless, too, and ever varying as you proceed. When you imagine that the last mountain rock or quarry contained the whole catalogue of Natural History, and showed you more than Goldsmith, or Buffon, you find that over the next ridge, or in the neighboring field, there are new subjects for study, and still renewing matters for wonder. If you have taken up your abode for the night at classic Rugby, at sporting Melton-mowbray, or among the academic bowers of Oxford, there are objects all around, in every hill-side, ravine, or railway section, to fill you at once with admiration and astonishment. Go, inquire of that rock. Go, inquire of that rock. It is the lias limestone; beyond it, and at no great distance, lies the oolite; and there, in the immediate vicinity of both, you have the Stonesfield slate. We invite you to examine any one of these common-place looking stones; and not in Gulliver, not in the history of the Knight of La Mancha, not in all the Mysteries of Udolpho, not in the |