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Page:Popular Science Monthly Volume 50.djvu/44

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32
POPULAR SCIENCE MONTHLY.

head of the glacier. The general appearance of things indicated that the glacier was diminishing in size, and Sissons told me that the surface of the glacier was at least from seventy-five to one hundred feet lower than at the time of his last visit, four years previous.

We lunched on the rim of the crater, at 3 p. m. went down to where we had left our horses, and after a hard and fatiguing though glorious ride of four hours reached the hotel ranch.

We found that the crater cone is composed of a reddish lava, while the mother peak rising far above it is formed of a hard, bluish trachyte. Its moraines extend for ten to twelve miles down the western slope, passing beyond the west side of the stage road north of Sissons, where more or less rounded hillocks of this bluish trachyte abut on the hills of metamorphic rocks of the Trinity and Sacramento Mountains.

We also saw as we descended that the large moraine extending from the cone ending in the "Devil's Garden" is flanked by two lateral moraines, the median one, or the garden, extending from the base of the crater cone. What adds to the singularity and wildness of the scene at the upper end of this "garden," or rather playground of mountain imps, are the numerous parallel concentric ridges of lava rock, forming a succession of transverse terminal moraines, with benches of clear soil between them. These parallel curved rows of stones and angular gravel mark the rapid retreat and melting away of the glacier, which, with its neighbor, extended down on the western slope.

To my disappointment, I found no Alpine fauna or flora on the summit of the crater, and believe there is none on the main peak. The vegetation was very scanty where we camped, only grasses and plants which had straggled up from below, and, so far as I remember, nothing but lichens occurred on the bare rocks and moraines above. No Alpine or arctic butterflies or moths occurred, such as I was familiar with, and which abound on the summits of the Rocky Mountains. A few spiders, a small centipede (Lithobius), and a few ants' nests were to be seen, and under stones a bristle-tail (Machilis), but the only distinctive Alpine insect on the mountain was a wingless grasshopper (Pezotettix), though that occurred lower down, in the zone of firs. I saw a common Pieris butterfly at the top of the crater, but this was like one seen flying below.

This entire lack of any Alpine plants or animals indicates that Mount Shasta is too young and isolated a mountain to have been reached by any waifs from arctic or Alpine sources, and their absence suggests that the glaciers had at a very recent date melted away and disappeared from the western side of the mountain.