The San Francisco Call
June 28, 1903
Crater Lake is Klamath County, Or., about seventy-five miles northeast of Grants Pass on the Shasta Route from San Francisco to Portland, is one of the most attractive geological fields in the world and equally inviting to those in search of great natural wonders, according to J. S. Diller of the United States Geological Survey, who for some time past has been engaged with a party in surveying that region.
“Lying in the summit of the Cascade Range, about midway between Mount Shasta and Mount Hood, Crater Lake remarkable for its position and size, but more especially on account of its beauty, its depth, the grandeur of its encircling cliffs and its history.The survey has been finished and a complete topographical map of Crater Lake and the vicinity has just been issued by the Government, with description and halftone illustrations, two of which with excerpts from the texts we here reproduce:
“It is approximately circular and averages a little more than five miles in diameter. It is reputed to be the deepest body of fresh water in America, having the remarkable depth of 2000 feet.
“The color of the water is ultramarine, bordered with turquoise along the shores. Set in majestic cliffs it is a natural jewel of great value to the State.
“Beautiful and attractive as the lake is, is serves but to conceal in large part the greater wonder, the stupendous pit or basin, the caldera, in which it is contained and from which the lake has taken its name. Although there are thousands of craters in this country, there is but one great caldera, and that contains Crater Lake.
“The average diameter at the top of the caldera is 5.7 miles, and its depth is 4000 feet. Nearly one-third of its bottom is over 100 feet below the level of Klamath Marsh, at the eastern foot of the Cascade Range. Where the lake is deepest soundings show the bottom to be approximately a plain several miles in extent. To the west it rises irregularly, culminating in two or more peaks, one of which reaches above the water and forms Wizard Island.
“The rim of the lake is the base of a truncated conical mountain hollowed to a shell. Upon the outside it slopes away at a comparatively small angle in all directions to the surrounding platform, but inside the descent of the lake is precipitous.
“The lake is completely girdled by a lofty escarpment ranging from 500 to 2200 feet in height, forming a picture which is beauty and grandeur is rarely equaled.
“Although the steep slopes of the escarpment are in some places well wooded, they are generally either cliffs or talus descending to the lake and plunging into deep water. There are but few points where the lake can be easily approached, and sandy beaches on its shores are few and small.
“Wizard Island, near the western border of the lake, is an excellent example of a small volcano. The cinder cone is symmetrical, composed chiefly of red lapilli, and in its top is a crater 150 feet deep.
“It is possible that the whole of the great pile of lava, over 2500 feet in height, which renders the western portion of the lake so much shallower than the eastern, has been escaped from this volcano. Soundings indicate two other cinder cones beneath the surface of the lake.
“As has been already remarked, the rim of the caldera is the trunk of a mountain cone. That this mountain was once complete is demonstrated by the altitude of the sheets of lava and ejected volcanic material which form the rim. They all incline away from the lake, indicating a common source from a crater that surmounted a high volcano high up in the air over place now occupied by the lake.
“At that time, of course, neither caldera nor lake existed. The original mountain which occupied this portion had been called Mount Mazama. The same topographic relations are indicated by the drainage. The canyons of Sand and Sun creeks do not, end with streams, but continue directly through the rim of the caldera to the cliffs overlooking the lake, forming notches. These canyons were carved into their present shape by the streams of ice and water descending from Mount Mazama.
“As to the height of this mountain we may get a suggestion by comparison. Mount Shasta and the rim of Crater Lake are of equal diameter at an altitude of 8000 feet, and being composed of essentially the same lavas and formed is the same way, it is probable that they would rise to nearly equal elevations. Some erosional features, however, suggest that Mount Mazama was the larger and probably in its day the greatest peak, of the Cascade range.
“The problem arises: How was this vast mountain, nearly six miles in diameter and possibly 5000 feet or more in height above, the present rim of the lake, removed and the stupendous caldera now occupied by Crater Lake produced? Did it go up or down?
“Mount Mazama collapsed and was engulfed and the great caldera was produced by subsidence. This view is singularly corroborated by an inflowing lava at the head of Cleetwood Cove-on the north side of the lake. It was still soft when Mount Mazama sank away and flowed down the inner slope, producing Rugged Crest.
“Afterward the engulfing eruptions began on the floor of the caldera and built up Wizard Island.
“The freshness of the lava of Wizard Island and the absence of all traces or erosion indicate that its volcano was active in comparatively recent geological time. The presence of so large a growth of forest trees, however, suggests that the eruption must have occurred centuries ago.
“Crater Lake has no visible outlet. Its surplus water escapes by, percolation and, in part at least, reappears again in the temperature of the water at the surface of the lake varies, but from a depth of 300 feet to the bottom it is uniformly about 39 degrees Fahrenheit.”
