the Coast Survey, to be distinctly marked upon the sea-bottom out to a point some eighty miles southeast of New York, and where the water is now over 500 feet deep. Here we reach the true margin of the continent, where the shore plunges rapidly down into the depths of the ocean; and here was for ages the mouth of the Hudson River; for the channel which leads to it could not possibly have been excavated except upon a land-surface.

2. Explorations made over a large part of the territory lying between the Atlantic and the Mississippi show that many of the draining streams are now flowing far above their ancient beds, and that these sometimes lie below the present ocean-level. For example, the Ohio flows in a valley the bottom of which is occupied by sand and gravel at least 100 feet thick. The rock-bottoms of the streams which empty into the Great Lakes are at their mouths sometimes 200 feet below the water-level. The Mohawk Valley is filled to a great depth with loose materials, the surface of which forms for long distances a nearly level plain, through which the present river meanders.

Innumerable instances of this kind could be cited, all of which

go to

prove that for ages the eastern half, at least, of this continent stood 500

to 600 feet higher above the ocean than now, and that during this time the draining streams with swiftly-flowing currents cut the surface into a network of deep channels not unlike the cañons of some of the rivers of the far West.

There seems to be good reasons for believing also that in this period of elevation the stream which drains the basin of the Great Lakes, called in different parts of its course the St. Mary's, the Detroit, the Niagara, and the St. Lawrence, flowed not through the modern channel, which passes the Thousand Islands and the Lachine Rapids, but, leaving the basin of Lake Ontario at its southeastern corner, traversed the now deeply-buried channel of the Mohawk, and entered the present valley of the Hudson somewhere near Albany-precisely where has not yet been determined, as heavy beds of drift cover and conceal its course for many miles in that vicinity. From Albany this ancient Hudson River flowed through a deeper and wilder valley than the present one, which is half filled with water, passed what is now New York Island, far below the present water-surface, was joined at the Battery by a large tributary from the east, issued from the highlands by a picturesque gate at the Narrows, and, traversing a littoral plain, emptied into the ocean eighty miles southeast from New York.

The limits of this article will not permit the presentation of all the facts which sustain this view, but a few of them will suffice to show that it hardly admits of doubt. These are briefly as follows:

An ancient connected line of drainage passes through the basin of the Great Lakes at least 200 feet below the present water-surface, deepening eastward, and reaching a level much below that of the bed of the St. Lawrence.

An old channel at least 200 feet deep connects Lake Huron and Lake Erie. Detroit is situated on the western side of it, and the rock lies there 130 feet below the surface.

Many of the streams now flowing into Lake Erie were once tributaries to the ancient river which traversed its valley and joined it far below the present water-level.

The old channel connecting Lake Erie and Lake Ontario apparently passed through Canada between Long Point and Hamilton. Heavy beds of drift, by which it is filled and concealed, here оссиру the surface. The Niagara now flows over a rock-bed, for this is a comparatively modern river, which, following the line of lowest surface-levels, passed over a spur from the south shore of the lake-basin when the old channel was filled by glacial drift.

Some of the streams draining into the basin of Lake Ontario in former times cut their channels below the present ocean-level. All the salt-wells of Syracuse are sunk in one of these, which is filled with gravel and sand saturated with brine issuing from the Salina group that forms its walls. The rock-bottom of this old river-bed was reached in some of these wells at a depth of fifty feet below the present level of tide-water.

The valley of the Mohawk is a very deep channel of erosion, now half filled, which must have been traversed by a large stream flowing eastward at a level below that of the present ocean; and everything indicates that this was the ancient outlet of the basin of the Great Lakes.

The channel of the Hudson is apparently the only possible continu

ation of this long line of drainage. As has been remarked, it is of great and yet unknown depth. The clay by which it is partially filled has been penetrated to a depth of about 100 feet along its margins. How deep it is in the middle portion can only be conjectured; but Hell Gate channel, which has been kept comparatively free by the force of the tides, is in places known to be nearly 200 feet deep; and, since this is a channel of erosion formed by a stream draining into the Hudson, the ancient bed of the Hudson must be still lower.

From the depth and distinctness of the old river-course on the submerged plain outside of the Narrows, we may reasonably infer that the old channel at New York is not much less than 300 feet deep.

We are compelled to conclude from these and other facts of similar import: 1. That the topographical features of the vicinity of New York were for the most part fashioned by the erosion of a system of watercourses which, in preglacial times, when the continent was higher than now, cut their valleys much deeper than would now be possible.

2. That there was here a group of hills composed of crystalline rocks, a sort of spur from the Alleghany belt, and that this range of hills was then seventy or eighty miles inland from the ocean, separated from it by a plain similar in its topographical relations to that which lies between the highlands of our Southern States and the present shore of the Atlantic.

3. At the period under consideration a river draining the basin of the Great Lakes, and in size the second on the continent, followed the course of the Mohawk and Hudson, and, passing through the New York hills, there left the highlands and flowed quietly on to the ocean.

4. Where New York Harbor now is, this great river received two important tributaries—one from the east through Hell Gate channel, which joined it at the Battery, the other from the west through the gorge of the Kill van Kull. Of these, the first is now represented by the Housatonic, then a larger stream, with a longer course and more tributaries; the second was formed by the Passaic and Hackensack, which united at the head of what is now Newark Bay, and emptied into the Hudson at the entrance to the Narrows. The junction of these two considerable branches so near each other seems to have produced the expansion of the valley which is now New York Harbor. This must then have been a very picturesque spot, as its outlet oceanward was a narrow pass bordered by the hills of Staten and Long Island, 500 feet in height. On the north, it was overlooked on one hand by the great wall of the Palisades, which rose 700 feet above the river; on the other, by a bold shoulder or headland, 400 feet in height, now New York Island, then a promontory, which separated the Housatonic and the Hudson to their junction at its southern extremity.

5. After the lapse of unnumbered ages, during which this nook among the hills was slowly prepared for the important part it was to play in the history of the yet unborn being-man-a quiet subsidence

VOL. XIII.-42

of the land or elevation of the water began in this region. Gradually the sea flowed in over its shores, crept up the valleys of the streams, checking their flow and converting them into tideways, until it washed the base of the highlands. Up to this time the surface of the littoral plain in its gradual submergence formed a broad expanse of shallow

water bounded by a monotonous line of beach, with no good harbors— a shifting, dangerous shore, such as is most dreaded by mariners. By further subsidence, however, the water flowed up into the valleys among the New York hills and into the deeper river-channels, making of the first safe, landlocked harbors, of the second navigable inlets or tideways. In this manner were produced the magnificent harbor and the system of natural canals connected with it, which determined the position and created the subsequent prosperity of the commercial emporium of the New World.

The subsidence which resulted in the formation of New York Harbor and its connections seems also to have affected all the coast, and the influx of the sea-water filled the valleys of the rivers which drained the Atlantic slope south of New York, and gave it the fringed and irregular outline which constitutes its most striking characteristic. James River, York River, the Potomac, the Susquehanna, and the Delaware, are, like the Hudson, half-drowned rivers-if we may use the expression-for all the lower portions of their valleys are estuaries, in which the tide sets up to the base of the highlands. But that portion of the littoral plain which separates these estuaries is too low, too much cut up with water-ways, and its harbors are too shallow and ill

Hence the

defined, to afford proper sites for great shipping-ports. cities of this region-Richmond, Washington, Baltimore, and Philadelphia-are situated at the head of navigation, where the rivers come down from the highlands on to the plain; and they are located like Albany, remote from the seaboard, with which they are connected by long and somewhat tortuous channels of inland navigation. New York, on the contrary, is located directly on the coast, because here alone the highlands reach to the sea, and their submerged valleys and river-channels form commodious, rock-girt harbors, immediately accessible from the ocean. It will be seen at a glance that this fact gives it great commercial advantages, and has been the most potent influence in making this the chief port of entry for the country.

FIG. 7.-MAP SHOWING OLD CHANNEL AND MOUTH OF THE HUDSON.

On the Southern coast there is no harbor at all comparable with that of New York except Norfolk. This is deep, roomy, and accessible to the sea-advantages which are destined to give it permanent and increasing importance. But it is less central to the population and business of the country; and, while its inland water connections through Chesapeake Bay and the tidal rivers which open into it are more extensive than those which the harbor of New York possesses, they are less favorably situated in their relations to the present and future internal commerce of the country.

The great advantage which New York enjoys for trade with the interior consists in its accessibility from the basin of the Great Lakes where the most rapid accumulation of population and wealth of the last half-century has taken place, and where the business of the country is destined to concentrate in the future. As has been stated in the preceding pages, the drainage of the lake-basin apparently flowed for