there was a cascade at Queenston of moderate height, which fell directly into the sea. The uppermost limestone and subjacent slate (8 and 7, fig. 4. p. 37.) being exposed, the cataract commenced its retrograde course, while the lower beds in the escarpment (from 6 to 1) were still protected from waste by remaining submerged. A second fall would in due time be caused by the continued rise of the land and the exposure of the hard beds (6 and 4), constituting what is called the Clinton group, together with the soft and easily undermined red shale (3), on which they repose. Finally, a third cascade would in all likelihood be produced by the rise of another hard mass, the quartzose sandstone (2, fig. 4.) resting on very destructible red shale (1). Three falls, one above the other, very similar in their geological and geographical position to those actually seen on the river Genesee at Rochester, would thus be formed. The recession of the uppermost must have been gradually retarded by the thickening of the incumbent limestone (No. 8, fig. 4), in proportion as the Falls sawed their way southwards. By this means the second cataract, which would not suffer the same retardation, might overtake it, and the two united would then be retarded by the large quantity of rock to be removed, until the lowest fall would come up to them, and then the whole would be united into one.

The principal events enumerated in the above retrospect, comprising the submergence and re-emergence of the Canadian lake district and valley of the St. Lawrence, the deposition of freshwater strata, and the gradual erosion of a ravine seven miles long, are all so modern in the earth's history as to belong to a period when the marine, the fluviatile, and terrestrial

shells, were the same, or nearly the same, as those now living. Yet if we fix our thoughts on any one portion of this period on the lapse of time, for example, required for the recession of the Niagara from the escarpment to the Falls,-how immeasurably great will its duration appear in comparison with the sum of years to which the annals of the human race are limited! Had we happened to discover strata, charged with fluviatile shells of recent species, and enclosing the bones and teeth of a Mastodon, near a river at the bottom of some valley, we might naturally have inferred that the buried quadruped had perished at an era long after the canoes of the Indian hunter had navigated the North American waters. Such an inference might easily have been drawn respecting the fossil tusk of the great elephantine quadruped, which I saw taken out of the shell-marl on the banks of the Genesee River near Rochester (see p. 19.). But fortunately on the Niagara, we may turn to the deep ravine, and behold therein a chronometer measuring rudely, yet emphatically, the vast magnitude of the interval of years, which separate the present time from the epoch when the Niagara flowed at a higher level several miles further north across the platform. We then become conscious how far the two events before confounded together,—the entombment of the Mastodon, and the date of the first peopling of the earth by man,-may recede to distances almost indefinitely remote from each other.

But, however much we may enlarge our ideas of the time which has elapsed since the Niagara first began to drain the waters of the upper lakes, we have seen that this period was one only of a series, all belonging to the present zoological epoch; or that in which

the living testaceous fauna, whether freshwater or ma rine, had already come into being. If such events can take place while the zoology of the earth remains almost stationary and unaltered, what ages may not be comprehended in those successive tertiary periods during which the Flora and Fauna of the globe have been almost entirely changed! Yet how subordinate a place in the long calendar of geological chronology do the successive tertiary periods themselves occupy! How much more enormous a duration must we assign to many antecedent revolutions of the earth and its inhabitants! No analogy can be found in the natural world to the immense scale of these divisions of past time, unless we contemplate the celestial spaces which have been measured by the astronomer. Some of the nearest of these within the limits of the solar system, as, for example, the orbits of the planets, are reckoned by hundreds of millions of miles, which the imagination in vain endeavours to grasp. Yet one of these spaces, such as the diameter of the earth's orbit, is regarded as a mere unit, a mere infinitesimal fraction of the distance which separates our sun from the nearest star. By pursuing still farther the same investigations, we learn that there are luminous clouds scarcely distinguishable by the naked eye, but resolvable by the telescope into clusters of stars, which are so much more remote, that the interval between our sun and Sirius may be but a fraction of this larger distance. To regions of space of this higher order in point of magnitude, we may probably compare such an interval of time as that which divides the human epoch from the origin of the coralline limestone over which the Niagara is precipitated at the Falls. Many have been the suc

cessive revolutions in organic life, and many the vicissitudes in the physical geography of the globe, and often has sea been converted into land, and land into sea, since that rock was formed. The Alps, the Pyrenees, the Himalaya, have not only begun to exist as lofty mountain chains, but the solid materials of which they are composed have been slowly elaborated beneath the sea within the stupendous interval of ages here alluded to.

The geologist may muse and speculate on these events until, filled with awe and admiration, he forgets the presence of the mighty cataract itself, and no longer sees the rapid motion of its waters, nor hears their sound, as they fall into the deep abyss. But whenever his thoughts are recalled to the present, the tone of his mind, the sensations awakened in his soul, will be found to be in perfect harmony with the grandeur and beauty of the glorious scene which surrounds him.

CHAPTER III.

Tour from the Niagara to the Northern Frontier of Pennsylvania.-Ancient Gypsiferous Formation of New York.-Fossil Mastodon at Geneseo.-Scenery.-Sudden Growth of New Towns.-Coal of Blossberg, and resemblance to British Coal Measures-Stigmaria.-Humming Birds.-Nomenclature of Places.-Helderberg Mountains and Fossils.—Refractory Tenants.—Travelling in the States.-Politeness to Women.-Canal-boat.-Domestic Service.Progress of Civilization.—Philadelphia.-Fire-engines.

Sept. 2. 1841.—FROM Niagara Falls we travelled to the large town of Buffalo, on the shores of Lake Erie, and then passed through Williamsville, Le Roy, and Geneseo, in the State of New York. The horizontal Silurian rocks of this region are in general extremely like those of corresponding age in Europe, consisting of mud-stones and limestone, with similar corals and shells. But there is one remarkable exception;-the occurrence in the middle of the series of a formation of red, green, and bluish grey marls with beds of gypsum, and occasional salt-springs, the whole being from 800 to 1,000 feet thick, and undistinguishable in mineral character from parts of the Upper New Red or Trias of Europe. Near Le Roy I saw these marls and the gypsum exposed to view in quarries. In the overlying limestone at Williamsville were large masses of corals, of the genera Favosites, Cystiphyllum, and others, in the position in which they grew. Some of the species agree with British fossils, but the greater part of them, as I may state on the authority of Mr. Lonsdale, who has studied my specimens, are distinct.