halk overlies the wealden, which was a mere delta at the river's outh. The bed of the river suddenly disappears, and now here rests upon it a deep sea formation. How stupendous and verwhelming the forces of nature through all her operations! How vast her affluence and prodigality, which could so thoroughly alter all her exterior and interior arrangements, and fill the seas with this new matter.

II. THE ORGANIC REMAINS display the boundless profusion of animal life which prevailed during the cretaceous period. The wealden furnishes no grounds of comparison, as that is simply a local fresh water deposit, and consequently can furnish no test of the general condition of life upon the surface of the globe. But when we go back to the oolitic period we obtain a standard by which to measure the doings of nature in the interval, what new creations started into being, and what provisions were made for their subsistence. The state of the temperature cannot be determined, as the products, with the rarest possible exceptions, are wholly marine, and therefore affected by atmospheric influences in a very small degree. Neither can much be conjectured concerning the state of the land, as scarcely a fragment of true terrestrial life has been detected in the deposit; and yet, from the stillness and comparatively small dimensions of seabasins into which the earthy ingredients were floated, the probability is that the land was both lofty and widely extended. One mammalian, and the remains of a solitary bird, and a meager sprinkling of vegetables, constitute the whole, and even dubious, amount of contributions from this department of nature. Neptune, therefore, the palæontologist turns his undivided attention; and, comparing one period with another, he finds the following results:

To

The cretaceous deposits all lie WITHIN THE AREA of the oolites. They are conformable generally in position, and display, in proportion to their extent, a like superabundance of calcareous earth. Hence a return to polyp and shelly types of life, which we find so characteristic and diversified in both epochs.

Thus of the first order, Amorphozoa, the oolitic age produced only one genus; in the cretaceous we find thirteen genera, in the

list Spongia, which is common to both. Of Zoophytes, there are twenty-three genera in the former, and seventeen in the latter-of which nine are common to both periods. The Echinodermata number eighteen in the oolite, and twenty-five in the chalk-five only common. The genus Foraminifera is entirely new in the latter formation, and consists of twelve ascertained genera, and nearly double the number of species. Of Annelida there are four genera in the oolite, and six in the chalk, in which the new order of Cirrhipeda occurs likewise. The Astacus is the only crustacean in the oolitic group: this and three new genera are found in the chalk. The Conchifera are very numerous in both deposits; forty-six in the older, and thirty-eight genera in the newer, of which eight are peculiar to the chalk. peculiar to the chalk. Monymaria are nearly in the same relative proportions. Rudistes occurs, as a new order, for the first time in the chalk, while again the Brachiopods, Gasteropods, and Cephalopods, are about equally abundant in both formations, with additions in the chalk to the generic models. And here too the new order Pteropoda, of a single genus and species, is introduced to our contemplation. Ammonites and Belemnites do not pass this age.

The fishes of the two periods are equally striking in their contrasts; the two orders of Ganoids and Placoids are common to

both, while the Ctenoids and Cycloids appear for the first time in the history of our planet, and which were afterward to contribute so largely to the sustenance and comforts of man. The Reptilians show a declension in the latter period in numbers, with the introduction, however, of four new genera-one of which (the Iguanodon Mantelli), is also found in the wealden.

Ex

The Cimoliornis Diomedeus, described by Professor Owen, is the only specimen of the order Aves or bird-tribe that as yet appears over this waste of waters. The term cimoliornis means simply the chalk-bird, and is allied, in some of its osseous processes, to the albatross, but also differs in too many points to be regarded as the ancestor of that courageous storm-braving animal. The claims of this fossil, indeed, to its true place in the system, have not yet been fully established. "Of the few actually fossilized remains of birds," says Professor Owen, "that have been discovered in England, the most complete and characteristic are those from the London clay. Some fragmentary Ornitholites have been discovered in the older pliocene crag, and in the newer pliocene fresh water deposits and bone caves. tremely scanty have hitherto been the recognizable remains of birds from the chalk formations. The fossil from the wealden, which I formerly believed, with Cuvier and Dr. Mantell, to belong to a wading bird, I have since adduced reasons for referring to the extinct genus of flying reptiles called Pterodactyle." The fossil bones of the Cimoliornis were obtained by the Earl of Enniskillen from the chalk beds near Maidstone, and resemble the humerus of the albatros in form, proportions and size; there are no distinct traces of the attachments of the quill-feathers in any of the fragments; but in other points there are analogies to the osseous structure of birds; and there are bones so gigantic as will assign them a place, if the proofs are completed, among the enormous foot-print class of the permian age, and go almost to realize the fabulous "roc" of the Arabian romance.

Our attention in this group of deposits, however, is riveted more by the little than the great-by the microscopic than the gigantic forms of life. It is astounding, indeed, to contemplate the myriads of creatures which swarmed in the seas during this period. A fragment of chalk, the size of a garden pea, contains

thousands of perfect shells; these shells inclose still, in many instances, the pulpy animal matter; and consist of a series of distinct well-defined chambers. In a cubic inch of the rock it is calculated that there are upward of a million of infusorial animalcules. Yet their orders are determined, their genera fixed, their very species are described, so perfect is the structure, and so thoroughly.preserved all the parts of their minute shelly coverlets. The microscope has restored, under the action of certain dilute acids, the contour and shape of entire hosts of these creatures. Some specimens, so positively can it speak of them, appear to consist of tubes placed edgewise,-one projecting sometimes beyond another. Others are seen to possess a series of tubular organs placed parallel, and disposed in long lines of fragile reticulated riband. Some are oblong figures. Others are complicated, exhibiting numerous projecting processes, and of every variety of shape. Some resemble the shell of the nautilus; others are still detected with the skin adhering to the skeleton; while in the stomachs and digestive sacs of others the more minute infusoria, which the diminutive monster had swallowed, are made palpable to the sight.

All this may be called trifling, a misapplication of talent, a waste of ingenuity. What terms too grand to describe the lofty speculations of the astronomer, who points his telescope to some dark point in the blue sky, and descries in its infinite depths a cluster of closely aggregated shining particles, minute as the motes in the sunbeam, and hails it as the discovery of a new system of worlds. He cannot count them, for they are innumerable. He cannot measure them, for they have no dimensions. He cannot tell their relations, nor describe their orbits of motion, for a sparkling heap of star-dust is all that flits before the reflector. But the boundaries of knowledge are enlarged, and though man nor any of the arts may ever be benefited thereby, the fortunate discoverer will have his name inscribed in that distant region of the universe, and transmitted from generation to generation with increasing

luster.

The discoveries of the geologist may be inferior in grandeur, but are they practically less illustrative in their bearings on existing arrangements? He sees the past in the present, the near and

e distant in time brought together. A charm is thereby thrown ver studies and speculations which would otherwise be useless. hus, in the mineral structures resulting from the agencies of nese invisible organic bodies, the mind is struck with the resemlance to similar processes that may be now going forward in the cean it sees in the discoloration of the waves, as the voyager teers his vessel over the main, a light by which to decipher the tory of an age; and, while no voice issues from the countless nyriads of animals which thicken the waters, rocks are elaborating and depositions made that will yet be raised into islands or continents. "On the coast of Chili, a few leagues north of Conception, the Beagle," says Dr. Darwin, "one day passed through great bands of muddy water, which, when taken up in a glass, was found to be slightly stained as if by red dust, and after leaving it for some time quiet, a cloud collected at the bottom. With a lens of one-fourth of an inch focal distance, small hyaline points could be seen, darting about with great rapidity, and frequently exploding. Examined with a much higher power, their shape was found to be oval, and contracted by a ring round the middle, from which line curved little setæ proceeded on all sides; and these were the organs of motion. The animals move with the narrow apex forward, by the aid of their vibratory cilia, and generally by rapid starts. Their numbers were infinite, and in one day we passed through two spaces of water thus stained, one of which alone must have extended over several square miles. The color of the water, as seen at some distance, was like that of a river which has flowed through a red clay district; but under the shade of the vessel's side, it was quite as dark as chocolate."

These are the foundation-builders of future islands, of the very color and size, it may be, as those which piled up these masses of the brick-red chalk. In an ounce of sea-sand, from three to four millions of these minute bodies have been enumerated. Twentytwo thousand can be placed side by side on a linear inch of surface. One single individual, in the course of a month in summer, will produce as many as 800,000,000. In a globule of water, a cubic inch contains more inhabitants than are now existing of the human family on the face of the globe. The skeletons of the animalcula are transported through the air in the form of a fine