River, out of which the tourist is supposed to have drunk at the only point where it shows itself (and there only to those who look for it), a quarter of a mile back. Another all-pervasive thing is the wholesome fragrance of arbor-vitæ. It is fitting, surely, that the tree of life should be growing in this floral paradise. There are few places, I imagine, where it flourishes better. On my way back toward the bridge I discovered, as was to be expected, many things that had been overlooked on my way out; and every successive visit was similarly rewarded. A pleasing sight at the bridge itself was the continual fluttering of butterflies--Turnus and his smaller and paler brother Ajax, especially--against the face of the cliffs, sipping from the deep honey-jars of the columbines. Here, too, I often stopped awhile to enjoy the doings of several pairs of rough-winged swallows that had their nests in a row of holes in the rock, between two of the strata. Most romantic homes they looked, under the overhanging ledge,--a narrow platform below, ferns and sedges nodding overhead, with tall arbor-vitæ trees a little higher on the cliff, and water dropping continually before the doors. One of the nests, I noticed, had directly in front of it a patch of low green moss, the neatest of door-mats. The holes were only a few feet above the level of the stream, but there was no approach to them without wading; for which reason, perhaps, the owners paid little attention to me, even when I got as near them as I could. In and out they went, quite at their ease, resting now and then upon a jutting shelf, or perching in the branches of some tree near at hand. Once three of them sat side by side before one of the openings, which after all may have admitted to some sizable cavern wherein different pairs were living together. They are the least beautiful of swallows, but for this time, at all events, they had displayed a remarkably pretty taste in the choice of a nesting-site.