hills, and their generally calcareous waters precipitated, by degrees, a bed of fine calcareous mud. To this were added the dead shells of myriads of little molluses that flourished upon the lime held by the waters. The bottom of each lakelet became a bed of marl. But all around the margins of the lakelet the grasses and sedges were vying with each other in venturing into the water. The amphib-. ious rushes put them both to shame by raising their dirty heads sheer through the slime of the lakelet's bottom. And there they stood-the rushes up to their knees in water, and the sedges and grasses scarcely over shoe. And every leaf and stem which fell upon the water or found its way to the shore, became entangled in the herbage, and lay down and rotted there; and the rush, and the sedge, and grass, when shrill November came,

"With wailing winds, and naked woods, and meadows brown and sear,"

bowed their heads in his presence, and wrapped themselves in the cerements that had gathered about them. Thus a soft bed of vegetable mould fringed the lakelet, and overlapped the deposit of marl which was growing beneath the water. From year to year, as the water shallowed about the margins, encroaching vegetation crowded farther and farther toward the centre of the lakelet. I have not seen the beginning of this process; but at that period of time in which I have been permitted to begin my observations, I find these changes in progress. I have detected Nature in mediis rebus. The little herb standing by the water's brink this year, dies, and forms a deposit exactly like that which was formed in the year before my eyes. or any human eyes-detected the character of these vicissitudes; and my logic compels me to reason from that which I have seen to that which no man has seen. And so it is of the changes upon the ocean's shore, until the facts of the passing world

are made to illuminate the dark and mysterious chambers of the fossil realm.

Reasoning thus, we are forced to the conviction that many of the ancient lakelets have become completely filled. Others are only half filled. Others have had the work completed even "within the memory of the oldest inhabitant." Who is not acquainted with some grassy pond which his father had known as a clear lakelet? What man is unable to point out some swale that in boyhood he had known as a grassy pond? or some meadow that he has traversed as an old-time swale? The work is not ended when the lakelet is filled. The surrounding eminences still continue to afford lime-yielding water, which saturates the muck and deposits its lime; while vegetation still pays its annual tribute to the accumulating stores, till the solid material becomes sufficient to exclude the excess of water. The ancient lakelet is at length a finished meadow. Man now steps in and appropriates the annual crop as coolly and unthinkingly, and perhaps as thanklessly, as if kind Nature had not expended a thousand years and infinite pains in fitting it up for his uses.

The epoch of the resurgence of the continent has been styled the Champlain Epoch of the Post-Tertiary Age. During this epoch existed the mastodon and mammoth, whose ponderous bones and teeth have overstrewn the entire area of our country. Unlike the teeth sown by Cadmus, those of these giant quadrupeds produced no crop, and we are not early enough in our visit to this planet to be gratified by the exhibition of living mastodons and hairy elephants.

It was probably also in the earliest part of the Champlain Epoch, or even before the full termination of the Glacial Epoch, that man appeared upon the earth. Judg ing solely from geological data, his appearance in America

was considerably later than in the Old World; but even in America the race has probably looked upon the later representatives of the mammoth and mastodon tribes. I have myself exhumed mastodon bones from a bed of peat not more than three feet deep, and which I believe could easily have been accumulated during the last five hundred years. The traditions of the American Indians in reference to the acquaintance of their ancestors with animals which left these gigantic remains are probably founded upon fact.

But this is a subject to which I shall return. I am tempted still to offer a few farther reflections upon the physical events marking the dawn of the Human Epoch.

H

IN

CHAPTER XXII.

FORMER HIGHER LEVEL OF THE GREAT LAKES.

N the spring of 1865, at the time of the memorable floods, I had occasion to pass over the Great Western Railway from Suspension Bridge to Detroit. From Chatham to the vicinity of Detroit this road runs within sight of Lake St. Clair. On this occasion the country was submerged almost as far as the eye could reach in every direction. Our engineer seemed to be practicing a new species of navigation rather grallatorial than natatorial. The little lake had become rampant. Outraged by the long encroachments of the land, it had decided to assert again its ancient supremacy. Then I was reminded, if I had never been before, how slight a rise in the lake would submerge entire counties lying upon its borders.

A large part of this Canadian peninsula is scarcely above the ordinary level of the lakes. The whole region looks like an ancient swale and a more ancient lake bottom. The same is true of a considerable breadth on both sides of Lake St. Clair and the Detroit and St. Clair Rivers. Lake St. Clair itself-except when rampant-is little better than a marsh with a river running through it. Among navigators it is the opprobrium of the lakes. One never ceases to hear sailors talk about "the flats," and Congress never ceases to be importuned to make another lake where Nature is in the very act of blotting one out. If the reader has ever taken a steam-boat trip through the lake, he could not avoid discovering that it is the very similitude of ostentatious learning-"all breadth and no depth." The

L

bullrushes are boldly invading and occupying it on every hand. A thousand incipient islands are breaking up its continuity. Once it was fifty miles in width and a hundred miles long. A rise of ten or twenty feet would make it that again.

But the whole series of lakes is nearly of the same level from Chicago to Buffalo. The former high waters of Lake St. Clair imply similar floods in the other lakes, Indeed, we easily discover corroboration of this in the topography of the country at Chicago, Detroit, and Toledo. These cities are built upon the slime of the lakes, and a slight elevation of the waters would bury them beneath a new deposit of lacustrine mud. The artesian wells of Toledo are supplied from some of the sandy beds of the ancient lake sediment, which follow the general configuration of the underlying drift, and come to the surface at some higher level back of the city.

These evidences of higher waters lead us to inquire for the cause. They could scarcely be occasioned by a greater volume of water, since the outlets are of sufficient capacity to prevent its accumulation. Nothing but an obstruction of the outlet can explain the phenomenon. This obstruction must have existed at a point where the contiguous shores were sufficiently elevated to prevent a flank movement of the water. It must also have existed at a point beyond or to the eastward of all these obvious traces of the inundation. It could not have been at Mackinac, for that would not have flooded Canada West. It could not have been at the foot of Lake Huron for the same reason, and because the contiguous country is too low. It could not have been at Buffalo for the last-named reason, and also because the country between Buffalo and Lake Ontario belongs to the submerged area. It must have been at the mouth of the Niagara River.