Nature Notes

Volume V No. 3 - September, 1932

Mystery At North Entrance
By Ranger R. P. Andrews

Creeping slowly up the shoulder of Mount Scott, the rising sun cast its first wan rays upon the slope of the northwest rim. The crest of the Rim was alive with a shimmering, opalescent light, for during the night the breeze from the north had stooped and brushed the earth with the summer's first white frost. The breeze had died, however, and now the air was hushed and still. Even the lake, far below, lay motionless in the gunmetal shadow of Cloud Cap. Gradually the sun cleared the shoulder of Scott, and its warmth became perceptible. And then occurred a curious thing. I became aware of a murmuring as of leaves stirred by a gentle breeze, but the air was motionless. I walked to where a group of hemlocks stood, seemingly immobile. Standing beneath them I looked up, but not a branch moved, not a twig quivered. Still that rustling murmur continued, and the air remained motionless. I walked back to my original place and listened. It was fainter now. The rustling had sunk to the merest whisper. I strained my ears. The sound was gone. The sun was well up now, and I could hear the throbbing of a motor approaching from the Diamond Lake Junction. Puzzled, I walked back to the cabin for my permit book.

For two days I pondered that peculiar susurration, that rustling of leaves from invisible trees. And three chilly mornings I rose before sunrise to be at the Rim to hear it. On the third morning I solved the mystery - mere by accident than by logic. Again everything was silent; the air motionless and the lake without a ripple. Again the earth was white with frost. Then, as the sun rose, the same gradually increasing rustle commenced, seeming to rise from the ground itself. I sat staring vacantly down the slope of the Rim, wondering. A slight movement a few feet down the slope attracted my eye, but I was too slow to catch it. Again I stared at the ground, this time with purpose. Four feet before my eyes a pebble shifted and rolled over twice. Another. And another. The whole slope was in motion toward the Lake! The mystery was solved!v

During the night tiny frost crystals had formed beneath these light pumice pebbles, raising them ever so slightly. The sudden heat of the rising sun melted these fragile supporting crystals instantaneously, and the pebbles dropped suddenly. Sometimes they would settle back into place, but more generally the abrupt shift of the pebble's equilibrium, situated as it was on a steep slope, would cause it to roll downward for a distance varying from a fraction of an inch to as much as four inches. The infinitesimal sound produced by this process, when multiplied several thousand fold, had produced in its totality a sound resembling that produced by a breeze in the forest. And thus slowly, with infinite patience, Nature was making use of one of her varied tools to accomplish here work of wearing down the Rim.

Forgotten Crater
By Ranger D. LeC. Evans

sketch of location of Forgotten Crater

To the geologist, that area traversed by the Rim Road presents a multitude of interesting features, all worthy of considerable study. Mazama Rock and the canyon at its base possibly deserves first place; the Hillman Pinnacles, Devil's Backbone, Llao Rock, Cottage Rocks, and precipitous drop below Cloud Cap appeal to the inquisitive mind of the student of physiography; lastly, U-shaped valleys; masses of fill, polished and grooved rocks, are a temptation to the individual who is glacier conscious.

Possibly because of the major distractions, a very interesting feature has not been described or forgotten as the case may be. It is the purpose of this short sketch to briefly describe it and its importance. Additional work is essential before the newest of cinder cones can be described with any detail.

Located four tenths of a mile west of Hillman Peak, this crater can be seen as one rounds the north side of the Watchman. A flat hill, capped with red, it terminates the ridge that runs down from the Hillman Peak in a westerly direction.

This volcanic outlet consists of two craters. The main crater has an approximate diameter of 300 feet and a depth of about 75 feet, and a small subsiding crater to the east of the main outlets has a 50 foot diameter and only a slight depth.

Preliminary observations might be tabulated as follows:

1. The cone displays two types of cinder material, black and red. The black occurs at the base, particularly on the north side. The cone of red cinders has been erected stop the black, and there is an abrupt steepening in slope as one enters the red cinder cone.

2. Two types of lava were observed. The earliest is a gray, glassy flow rock which is perchance the equivalent of the Basic Andesite of Wizard Island. The latest is a rock showing excellent flow structure and is Dacitic in character, although it might be a Rhyolite when examined in thin section. This same rock without flow structure plugs the old outlet.

3. The cinders make up the north and east sides of the cone, the flow rocks form the south side and the western portion is open. Thus, the shape is that of a horse shoe.

Crater Lake National Park has been known for its adnate cones, its other smaller volcanic outlets existing as satellites about the base of an older and greater volcano. Red cone, 2.4 miles northwest of the water's edge has always been considered the nearest. This cone (shall we call it Forgotten Crater) is by far the closest to the Lake area, being about eight tenths of a mile northwest of the Rim.

The Park area has always boasted of a simplicity of rock types. The write believed that this cone presents something that is not Andesite, Dacite or Basalt.

In conclusion, the case with which this point can be reached makes it quite attractive. Many people cannot make the more strenuous trips - to Wizard Island, Red Cone and Crater Peak, to investigate the signs of our most recent volcanic action. A short ten minute walk from the saddle behind Hillman Peak enables people to see a real cinder cone, contemporaneous in time, I believe, with that action which erected Wizard Island.

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