The fine entrance is of grey limestone in undisturbed horizontal strata, and this is so plainly marked in the roof-supporting pillars as to give them the appearance of having been prepared by skillful hands, in several blocks, and afterwards arranged in place without the aid of mortar. Unfortunately, all efforts to photograph this wonderful portico have failed to give satisfaction--its position above the river being such as to afford no point for the proper placing of the camera; but a second visit made for the purpose of trying was far from being a loss, and part of the reward consisted of finding among the sheltered rocks, scarcely three feet above the floor, two humming birds' nests with their treasure of small eggs, and our little companion who discovered them was pleased to leave them untouched. SUGAR TREE HOLLOW CAVE. The name of this cave is due to the fact that the approach is through a "hollow" well wooded with sugar maple trees. It is two miles from Galena and the drive a beautiful one, as much of the way is through the forest without a road, but with a charming little rushing, crooked stream of clear, cold water: and in places the green slopes give way to mural bluffs of grey limestone in undisturbed strata. The entrance to the cave is through a hole about two feet high by three in width, into which we went feet first and wiggled slowly down an incline covered with broken rock, for a distance of fifteen feet, where a standing depth is reached. A flat, straight, level ceiling extends over the whole cave without any perceptible variation, and this is bordered around its entire length and breadth with a heavy cornice of dripstone, made very ornamental by the forms it assumes, and the multitude of depending stalactites that fall as a fringe around the walls. The line of contact between the cornice and ceiling is as clear and strong as if both had been finished separately before the cornice was put in place by skillful hands. Dripstone covers the walls, which vary in height from one foot to twenty feet, according to the irregularities of the floor, just as the width of this one-room cave varies with the curves of the walls, which are sweeping and graceful, the average being twenty-nine feet, but is much greater at the entrance where the entire slope extends out beyond the body of the cave. The length, from north to south, measures two hundred and thirty-three feet exclusive of an inaccessible extension. The south end of the cave rises by a steep slope to within a foot of the ceiling with which it is connected by short but heavy columns of dripstone, and another line of pillars of graduated height meets this at right angles near the middle and ends in an immense stalagmite that stands at the foot of the slope like a grand newel post.