"Doubtless, the greater portion of the water which flows in the Silver Spring River is furnished by this principal or head-spring; but there are several tributary springs of similar character along the course of the stream, which contribute more or less to the volume of water. These usually occur in deep basins, or coves, along the margin of the stream. The depth of one of these coves, situated about two hundred yards below the head-spring, was found to be thirty-two feet in the crevice in the limestone bottom from which the water boiled; in other deep parts of the basin the depth was about twenty-four feet. The 'Bone-yard,' from which several specimens of mastodon bones have been taken, is situated two miles below the head-spring, it being a cove, or basin, measuring twenty-six feet. "The most remarkable and really interesting phenomenon presented by this spring is the truly extraordinary transparency of the water--in this respect surpassing any thing which can be imagined. All of the intrinsic beauties which invest it, as well as the wonderful optical properties which popular reports have ascribed to its waters, are directly or indirectly referable to their almost perfect diaphaneity. On a clear and calm day, after the sun has attained sufficient altitude, the view from the side of a small boat floating on the surface of the water, near the center of the head-spring, is beautiful beyond description, and well calculated to produce a powerful impression upon the imagination. Every feature and configuration of the bottom of this gigantic basin is as distinctly visible as if the water was removed, and the atmosphere substituted in its place. "A large portion of the bottom of this pool is covered with a luxuriant growth of water-grass and gigantic moss-like plants, or fresh-water algæ, which attain a height of three or four feet. The latter are found in the deepest parts of the basin. Without doubt, the development of so vigorous a vegetation at such depths is attributable to the large amount of solar light which penetrates these waters. Some parts are devoid of vegetation; these are composed of limestone rock and sand, presenting a white appearance. The water boils up from fissures in the limestone; these crevices being filled with sand and comminuted limestone, indicate the ascending currents of water by the local milk-like appearance produced by the agitation of their contents.