denudation south of Lake Ontario was such as to reduce it three hundred feet below the level of the terrace on which Buffalo is situated. Lake Ontario is three hundred and thirty-four feet lower than Lake Erie. The deep cut of the narrow lakes south of Ontario bespeaks a powerful current from that quarter towards the central stream.

That the terrace running along the shore of Lake Erie was covered by water for a long period after the ridge bounding it on the south was dry, is indicated by the fact that there are many ancient fortifications, mounds, and other remains on that ridge, but none on the terrace at its feet. As the terrace is level, fertile, and contiguous to the water, fortifications and mounds would naturally have been erected on that, as well as on the higher grounds that stretch along by its side, had it then stood at its present elevation above the lake. The total absence of those works throughout its whole line, indicates that there was some insuperable obstacle to their erection there; and what can that have been, but that that level still lay beneath the waters, and the ridge by which it is bounded formed the shore of the lake?

Let us now turn to the process by which the channel of the Niagara was formed. Some geologists, reasoning from the rate at which the recession now takes place, maintain that sixty thousand years must have been consumed in cutting the gorge from Lewistown up to its present head. Mr. Lyell estimates the period at thirty-seven thousand. On the supposition, however, that it took place, as we have suggested, by the sudden break of a mountain barrier four hundred miles or more north, in consequence of which the channel of the St. Lawrence was cut, and the waters drawn in a great measure from the area above, they had before occupied, the excavation of the Niagara gorge must have been accomplished in a brief period. The rush of the flood naturally cut down and denuded the country on both sides of the principal current, and left the terrace that now runs along the margin of Ontario, at a level three hundred feet below the Erie terrace. The Niagara channel was in like manner excavated at that time, and instead of occupying thousands of years, was the work of but a few weeks, or perhaps days.

Confirmations of this are furnished by the present condition of portions of the Erie terrace. The canal from Buffalo runs along that terrace on a dead level till it reaches Lockport at the distance of twenty-four miles, where the earth descends from the Erie to the Ontario terrace. Throughout that line from Buffalo, for more than twenty miles, the canal is cut through a bed of clay. On approaching the crest of the Erie terrace on which Lockport stands, it passes into rock; which at the junction is of precisely the same height and color as the clay. This indicates that the rock was originally clay, and has been changed to its present form by the drainage of the water with which it was once saturated, into the Ontario valley that runs along at the foot of the level of which it forms the edge. As the slope to that lower ground let off its extra moisture, it became indurated, while the clay above, permeated with the water of the Tonnewanda, continued in a plastic state. And as this is the terrace through which the channel of the Niagara runs, it is apparent that that chasm may have been cut with great rapidity. On the supposition that anterior to the break of the northern chain of mountains by which the channel of the St. Lawrence was opened, the country now bounding the Ontario was at the same level as the Erie terrace on the giving way of that barrier, the whole mass of the sedimentary deposits being then soft like the clay of the Tonnewanda swamp, the waters would naturally greatly reduce by denudation the level of the Ontario region, and might in a few days have ploughed back the channel of the Niagara to near the present falls. On the desiccation of the edges of the gorge, they were hardened into rock, and frost and other agents throwing off masses and fragments from time to time,. have at length given them their present jagged appearance. That the upper strata at the falls and at Lockport were originally the same, is indicated by the fact that the present surface stratum at each is limestone, while that which liesimmediately beneath it, at each, is a friable shale.

Such in our judgment was the origin of the strata that are spread over the wide spaces drained by the Mississippi and the Lakes, and such the agents by which so large a share of them along the river channels and borders of the lakes were swept off, and the country left in its present con41

VOL. XIII.-NO. IV.

formation. We might add many corroborative facts from that and other regions; but we content ourselves with these brief statements, in the hope that they may attract the notice of scientific inquirers, and lead to a careful test, especially of the views we have advanced of the agency of chemical forces in the formation of the strata, and of their title to be assigned a like office in the construction of the deposits of other regions.

ART. VIII-BURTON'S TRAVELS IN THE LAKE REGIONS OF CENTRAL AFRICA.

THE LAKE REGIONS OF CENTRAL AFRICA.-A Picture of Exploration. By RICHARD F. BURTON, Capt. H. M. I. Army, Fellow and Gold Medalist of the Royal Geographical Society. New York: Harper & Brothers.

THE region visited by Capt. Burton in the journey he here details, is far less attractive than that of the Niger, explored by Dr. Barth, or the Zambesi, traversed by Dr. Livingstone. Lying near the equator, the rains and heats are excessive, the vegetation rank, and the exhalations that continually steam from its decaying masses so noxious, as to place the life of strangers at hazard, the moment they begin to inhale their poisoned particles. Scarce a trace of any but the rudest cultivation appears in any part of the region. The population are savages of the lowest caste, idle, wild, brutal, ferocious in the extreme; and wasting their powers in continual forays, for vengeance, plunder, and the seizure of captives to be sold into slavery. In everything that belongs to humanity they are as much below the blacks in this country, free or bond, as these are beneath the whites of the highest order of intelligence, refinement, and sensibility, and purity and elevation of affections.

Captain Burton left Kaole, on the coast opposite Zanzibar, at the close of June, 1857, attended by a number of guides who had before traversed the route, a guard furnished by a Zanzibar chief, and a gang of porters, whose office it

was to lead the asses bearing the tents, merchandise, and food, and to carry burdens. There are no roads, but only rude. paths through open levels, along the foot of hills, through groves, thickets, and swamps. The line for the first hundred miles was mainly along the Kingari and Mgeta rivers, and has an elevation of but two to three hundred feet above the sea. The next stage carried them over the Usagara mountains, which reach at their highest point, five thousand seven hundred feet above the ocean, and terminate on their western slope in a table land that extends to the Lake Tanganyika, at an elevation varying from two to four thousand feet. Much of this higher region is nearly as unhealthy as the low lands east of the Usagara range, partly from the excessive moisture, heat, when the sun pours his unobstructed blaze, and decaying vegetation; and partly from the cold blasts that sweep frequently from the mountains.

The inhabitants of the west consist of half-caste Arabs, and native clans. Both are of a very low order.

"The half-caste Arab is degenerate in body and mind. The third generation becomes as truly negroid as the inner heathen. Even creoles of pure blood born upon the island and the coast of Zanzibar, lose the high nervous temperament that characterizes their ancestors, and become, like Banyans, pulpy and lymphatic. The mestizos appearing in the land of their grandsires, have incurred the risk of being sold as slaves. The peculiarity of their physiognomy is the fine Semitic development of the upper face, including the nose and nostrils, while the jaw is prognathous, the lips are tumid and everted, and the chin is weak and retreating. Idle and dissolute, though intelligent and cunning, the coast Arab has little education. . . .

"The Wamrima, or coast clans, are of darker complexion, and are more African in appearance than the coast Arabs. The popular color is a dull yellow bronze. The dress is a Fez, or a Surat cap; a loin cloth, which among the wealthy is generally an Arab check or an Indian print, with a similar sheet thrown over the shoulders. Men seldom appear in public without a spear, a sword, or a staff; and priding themselves upon the possession of umbrellas, they may be seen rolling barrels or otherwise working upon the sands, under the luxurious shade. The women wear a tobe or long cloth, wrapped tightly around the body, and extending from beneath the arms to the ankles. The free

woman is distinguished from the slave-girl, when outside of the house, by a cloth thrown over the head. Their favorite necklace is a string of sharks' teeth. They distend the lobes of the ears to a prodigious length, and decorate them with a rolled up strip of variously dyed cocoa-leaf, a disk of wood, a betel-nnt, or a few straws. The left wing of the nose is also pierced to admit a pin of silver, brass, bead, or even a bit of manioc-root. The hair, like the body, is copiously anointed with cocoa-nut or sesamum oil."-Pp. 42-47.

The following is a picture of the country on the Kingani.

"In the evening I walked down to the bed of the Kingani river, which bisects a plain all green with cultivation-rice and holcus, sweet potato and tobacco, and pleasantly studded with huts and hamlets. The width of the stream, which runs over a broad bed of sand, is about fifty yards; it is nowhere fordable, as the ferry-boat belonging to each village proves; and thus far it is navigable, though rendered dangerous by the crocodiles and the hippopotami that house in its waters. The color is tawny, verging upon red, and the taste is soft and sweet, as if fed by rain. The Kingani, like all streams in this part of the continent, is full of fish. The night was rendered uncomfortable to the Baloch (guides), by the sound of distant drums, which suggested fighting as well as feasting, and by the uproar of the wild men, who, when reconnoitred by the scouts, were found to be shouting away the hippopotami.

"In the hurry and confusion of loading on the next morning, one ass was left behind, and the packs were so badly placed that the fatigue of marching was almost doubled by their repeated falls.... After marching a few miles over undulating ground, open and park-like, and crossing rough and miry beds, the path disclosed a view verging upon the pretty. By the way side was planted the peculiarly African Mzimu or fetiss hut, a pent-house about a foot high, containing as votive offerings ears of holcus, or pombe-beer in a broken gourd. There, too,. the graves of the heathen met the eye. In all other parts of Eastern Africa, a mouldering skull, a scattered skeleton, or a few calcined bones, the remains of wizards and witches dragged to the stake, are the only visible signs of man's mortality. The tombs, especially those of chiefs, resemble those of the Wamrima. They are parallelograms, seven feet by four, formed by a regular dwarf paling that incloses a space cleared of grass, and planted