| FIGURE 4—Diagram illustrating the Formation of marginal Crevasses. |
29 The Forms of Water: International Scientific Series, New York, 1875, pp. 107–108.
The explanation given above applies especially to the lower or icy portion of a glacier; above the snow-line other facts appear. When a glacier flows through fields of snow on a level with its surface, crevasses are formed in the adjacent banks. These trend down stream for the same reason that the crevasses in the glacier proper trend up stream—that is, the friction of the moving stream against its banks tends to carry them along, while the portions at a distance are stationary. Fissures are thus opened which trend in the direction in which the glacier moves. The angle made by these crevasses with the axis of the glacier is about the same as those of the marginal crevasses, but in an opposite direction. They are widest near the margin of the glacier and taper to a sharp end towards the stationary snow-banks above. The crevasses in the two series thus fall nearly in line, but are separated by a narrow band of irregularly broken snow, marking the actual border of the glacier.29
30 Crevasses in snow-fields through which ice-streams flow will be mentioned again in describing the Seward glacier.
After leaving Blossom island the party was divided, and we began a new series of numbers for our camp above the snow-line, although in this narrative and on the accompanying map a single series of numbers for all the camps will be used. While in the field the camps in the snow were usually termed, facetiously, "sardine camps," in allusion to the uncomfortable manner in which we were packed in our tent at night.
ACROSS PINNACLE PASS.
The morning after reaching Camp 12 dawned gloriously bright. The night had been cold, and a heavy frost had silenced every rill from the snow-slopes above. The clear, bracing air gave us renewed energy and a firmer desire to press on. Mr. Kerr and myself made an excursion ahead, while Lindsley and Crumback brought up a load of supplies from the cache left on the glacier below Camp 11.
On gaining the center of the Marvine glacier we had a magnificent view down the broad ice-stream, bordered on either hand by towering, snow-laden precipices, and changing, as the eye followed the downward slope, from pure white to brown and black in the distance. Far below we could barely discern the wooded summit of Blossom island, beyond which stretched the seemingly limitless ice-fields of the Malaspina glacier. All about us the white slope reflected the sunlight with painful brilliancy, while the black moraines and forests below and the mists over the distant ocean, made it seem as if one was looking down into a lower and darker world.