Page:Popular Science Monthly Volume 58.djvu/518

510 by Pyramid Lake the springs were more numerous and the water consequently more richly impregnated with lime. As a result, we find to-day in and about this lake the most interesting and remarkable tufa deposits known in all the Great Basin.

The tufa deposits are of various sorts and appearances, the differences being due to changes in the chemical properties of the water at various stages. Some of the forms are merely encrusting, and apparently structureless. Others show beautiful dendritic and interlacing figures, lapping over each other like the successive branches of some organic growth. The great deposits in Pyramid Lake have been built up in the form of towers, domes and pinnacles. The smaller ones bear a most striking resemblance to great thick mushrooms with a concentric

structure. These mushroom-like growths start from some projecting point or pebble and increase in size by precipitation from the surrounding water, until, massing together, the great domes and pinnacles have been built up, rising hundreds of feet in the air.

While these deposits are still being formed in Pyramid Lake, the large ones which rise so picturesquely from the water must, of course, have been formed before Lake Lahonton had entirely disappeared, and it has been only through the continued recession of the water that the deposits have become exposed to our observation.

Following the road northward along the west side of the lake, we pass many curious forms assumed by the tufa. Here is one upon a