THE BLUFF AT DECORAH.
From a Photograph by Mr. A. F. Kovarik.
About four kilometers west of Watertown, on the south bank of the Black River, is the picnic ground of Glen Park, which is reached by trolley. The manager of the restaurant walked around the park with me. In one spot is a hollow or glen at the base of a small, much cracked limestone cliff, which has a northern exposure. The manager said that snow and ice usually lies in this place until June, not only among the broken rocks, but even in the open. Sometimes ice remains among the boulders all summer, but only near the front of the boulders, and by pushing in, one soon gets beyond it: we found none, a fact showing once more the effect of the unusually warm summer. On hot days, draughts issue from between the boulders, but as the day was cool, we did not notice any. The spot is well sheltered against the wind by a number of trees; and the shape of the hollow reminded me of the glen in front of the Eishöhle bei Roth.
Not one hundred meters from this hollow, is a little limestone cave, closed by a wooden door, which excludes any cold air in winter. The cave is lighted by electric lights, and is a narrow, crooked, descending fissure, a ganghöhle, where the marks of water action are plainly visible. At the bottom a little stream, evidently the active agent in forming the cave, ran through the fissured limestone. In the stream a large toad or frog was swimming about. There was nothing icy about the cave or the water, and the temperature was normal. Ice was never known to form in the cave. These two places, so close together, are an interesting confirmation that it is only where the outside cold can get in, that we find subterranean ice.
THE FREEZING CAVE AND FREEZING WELLS OF DECORAH.
Near Decorah, Iowa, is a freezing cavern, which is more frequently referred to in cave literature than is generally the case. I visited it on Friday, September the 30th, 1898, with an old English resident of Decorah, Mr. W. D. Selby-Hill. The cave is situated about one kilometer to the northward of Decorah, on the north bank of the Upper Iowa River, at the base of a bluff. It is some thirty to forty meters above the stream, and faces southward. It looks like a fault or fissure in the rocks, with the sides meeting a few meters overhead. It is a true cave, but probably in an early stage of formation, for there are no apparent traces of water action, nor any stalagmites nor stalactites. The absence of the latter may, however, be due to the fact that it is a periodic glacière. The rock is a white limestone, rich in fossils. The cave is some two to three meters in width and is rather winding, with a short arm or pocket branching out on the west side. The main cave runs back some thirty meters from the entrance. In one place it is necessary to stoop, to get past some overhanging rock slabs. By candle light, we went to the rear of the cave, and found it warm, dry, and free from ice. There were no draughts, possibly because the day was cool.
