Let my theorizing be true or false, I greatly enjoyed the picture; the deep, dark, wooded ravine, with the line of water running through it lengthwise, the magnificent stone arch, the low hills in the middle distance, and Thunder Mountain a background for the whole. The mountain, as has been said, was a long ridge, not a peak; and sharp as it looked from this point of view, it was very likely flat at the top. Like Lookout Mountain and Walden’s Ridge, it might, for anything I knew, be roomy enough to hold one or two Massachusetts counties upon its summit. While I sat gazing at it the sun went down and left it of a deep sombre blue. Then, of a sudden, a small heron flew past, and a pileated woodpecker somewhere behind me set up a prolonged and lusty shout; and a few minutes later I was startled to see between me and the sunset sky a flock of six big herons flying slowly in single file, like so many pelicans. From their size they should have been _Ardea herodias_, but in that light there was no telling of colors. It was a ghostly procession, so silent and unexpected, worthy of the place and of the hour. I was beginning to feel at home. A wood thrush sang for me as I continued my course to the hotel, and my spirit sang with him. “I’m glad I am alive,” my pencil wrote of its own accord at the end of the day’s jottings. I woke the next morning to the lively music of a whippoorwill,--the same, I suppose, that had sung me to sleep the evening before. He performed that service faithfully as long as I remained at the Bridge, and always to my unmixed satisfaction. Whippoorwills are among my best birds, and of recent years I have had too little of them. Immediately after breakfast I must go again to the roadside wood, and then to Buck Hill, as a dog must go again to bark under a tree up which he has once driven a cat or a squirrel. But there is no duplicating of experiences. The birds--the flocks of travelers--were not there. Chats were calling _ceow, ceow_, with the true countryman’s twang; and what was much better, a Swainson thrush was singing. Better still, a pair of blue yellow-backed warblers (the most abundant representatives of the family thus far) had begun the construction of a nest in a black-walnut-tree, suspending it from a rather large branch (“as big as my thumb”) at a height of perhaps twenty feet. It was little more than a frame as yet, the light shining through it everywhere; and the bird, perhaps because of my presence, seemed in no haste about its completion. I saw her bring what looked like a piece of lichen and adjust it into place (though she carried it elsewhere first--with wonderful slyness!), but my patience gave out before she came back with a second one.