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stones resting on the slippery slope beneath. Fortunately, the crevasses were mostly filled with stones fallen from the sides, so that the danger from open fissures, which has usually to be guarded against in glacial excursions, was obviated; yet, as is usually the case when crevasses become filled with débris, the melting of the adjacent surfaces had caused them to stand in relief and form ridges of loose stones, which were exceedingly troublesome to the traveler.

Near the western side of the Lucia glacier, between Terrace point and Floral pass, there is a huge rounded dome of sandstone rising boldly out of the ice. This corresponds to the "nunataks" of the Greenland ice-fields, and was covered by ice when the glaciation was more intense than at present. On the northern side of the island the ice is forced high up on its flanks, and is deeply covered with moraines; but on the southwestern side its base is low and skirted by a sand plain deposited in a valley formerly occupied by a lake. The melting of the glacier has, in fact, progressed so far that the dome of rock is free from ice on its southern side, and is connected with the border of the valley toward the west by the sand plain. This plain is composed of gravel and sand deposited by streams which at times became dammed lower down and expanded into a lake. Sunken areas and holes over portions of the lake bottom show that it rests, in part at least, upon a bed of ice.

The most novel and interesting feature in the Lucia glacier is a glacial river which bursts from beneath a high archway of ice just at the eastern base of the nunatak mentioned above, and flows for about a mile and a half through a channel excavated in the ice, to then enter the mouth of another tunnel and become lost to view. An illustration of this strange river and of the mouth of the tunnel in the débris-covered ice into which it rolls, reproduced from a photograph by a mechanical process, is given on plate 14 (page 110), and another view of the mouth of the same tunnel is presented in the succeeding plate. This is the finest example of a glacial river that it has ever been my good fortune to examine.

The stream is swift, and its waters are brown and heavy with sediment. Its breadth is about 150 feet. For the greater part of its way, where open to sunlight, it flows between banks of ice and over an icy floor. Fragments of its banks, and portions of

[graphic][subsumed][subsumed]

ENTRANCE TO AN ICE TUNNEL; FORMERLY THE OUTLET OF A GLACIAL LAKE.

[blocks in formation]

the sides and roof of the tunnel from which it emerges, are swept along by the swift current, or stranded here and there in midstream. The sand plain already mentioned borders the river for a portion of its course, and is flooded when the lower tunnel is obstructed

The archway under which the stream disappears is about fifty feet high, and the tunnel retains its dimensions as far as one can see by looking in at its mouth. Where the stream emerges is unknown; but the emergence could no doubt be discovered by examining the border of the glacier some miles southward. No explorer has yet been bold enough to enter the tunnel and drift. through with the stream, although this could possibly be done without great danger. The greatest risk in such an undertaking would be from falling blocks of ice. While I stood near the mouth of the tunnel there came a roar from the dark cavern within, reverberating like the explosion of a heavy blast in the chambers of a mine, that undoubtedly marked the fall of an ice mass from the arched roof. The course of the stream below the mouth of the tunnel may be traced for some distance by scarps in the ice above, formed by the settling of the roof. Some of these may be traced in the illustrations. When the roof of the tunnel collapses so completely as to obstruct the passage, a lake is formed above the tunnel, and when the obstruction is removed the streams draining the glacier are flooded.

At the mouth of the tunnel there are always confused noises and rhythmic vibrations to be heard in the dark recesses within. The air is filled with pulsations like deep organ notes. It takes but little imagination to transform these strange sounds into the voices and songs of the mythical inhabitants of the nether regions.

Toward the right of the tunnel, as shown on plate 14, there appears a portion of the former river bed, now abandoned, owing to the cutting across of a bend in the stream. The floor of this old channel is mostly of clear, white ice, and has a peculiar, hummocky appearance, which indicates the direction of the current that once flowed over it. A portion of the bed is covered with sand and gravel, and along its border are gravel terraces resting on ice. These occurrences illustrate the fact that rivers flowing through channels of ice are governed by the same general laws as the more familiar surface streams.

After examining this glacial river, during our first excursion on the Lucia glacier, we reached its western banks by crossing

above the upper archway. Traversing the sand plain to the westward, we came to another stream of nearly equal interest, flowing along the western margin of the glacier, past the end of the deep gorge called Floral pass. A small creek, flowing down. the pass, joins the stream and skirts the glacier just below the mouth of a wild gorge on the side of the main valley. This stream once flowed along the border of the Lucia glacier when it was much higher than now, and began the excavation of a channel in the rock, which was retained after the surface of the glacier was lowered by melting. It still flows in a rock-cut channel for about a mile before descending to the border of the glacier as it exists at present. The geologist will see at once that this is a peculiar example of superimposed drainage. The gorge cut by the stream is a deep narrow trench with rough angular cliffs on either side, and is a good example of a water-cut cañon. When the Lucia glacier melts away and leaves the broadbottomed valley clear of ice, the deep narrow gorge on its western side, running parallel with its longer axes, but a thousand feet or more above its bottom, will remain as one of the evidences of a former ice invasion.

During our reconnoissance we turned back at the margin of the second river, but a day or two later reached the same point with the camp hands and camping outfit, and, placing a rope from bank to bank, effected a crossing. Our next camp was in Floral pass. From there we occupied a topographical station on the summit of the Floral hills, and made another reconnoissance ahead, across the Hayden glacier,* to the next mountain spur.

Floral pass, like so many of the topographical features examined during the recent expedition, has a peculiar history. It is a comparatively low-grade gorge leading directly across the end of an angular mountain range forming one of the spurs of Mount Cook. The position of the pass was determined by an east-andwest fault and by the erosion of soft shales turned up on edge along the line of displacement. At its head it is shut in by the Hayden glacier, which flows past it and forms a wall of ice about two hundred feet high. The water flowing out from beneath the side of the glacier forms a muddy creek, which finds its way over a bowlder-covered bed in the bottom of the gorge to the border of Lucia glacier. Along the sides of the gorge there are

* Named in honor of the late Dr. Ferdinand V. Hayden, founder of the United States Geological Survey of the Territories.

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