After examining this glacial river, during our first excursion on the Lucia glacier, we reached its western banks by crossing {108} 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 broad-bottomed 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_,[28] to the next mountain spur. [Footnote 28: Named in honor of the late Dr. Ferdinand V. Hayden, founder of the United States Geological Survey of the Territories.]