The great cavern of Wookey-Hole is situated two miles to the north-west of the city of Wells, in the centre of Somerset, and immediately adjacent to the thriving- village which has taken the name of the cavern, and has depended for its prosperity on the existence of the copious and usually pellucid stream, which here bursts forth from Mendip's hidden reservoirs. This is the source of the Axe, which winds its way through the lower lands, and after uniting with the sister stream of Cheddar, flows into the sea near Weston-super-mare. From Wookey-Hole the southern slope of Mendip rises in an unbroken sweep till it reaches a thousand feet above the sea, commanding a magnificent view to the east, south, and west. It is not a limestone cave in the ordinary sense of the word, since every known cavity in the immediate vicinity is not in the Carboniferous Limestone, but in the Dolomitic Conglomerate, which here attains enormous thickness. To the north, the great mass of Carboniferous Limestone, receiving the water of innumerable springs from the Old Red Sandstone and Shales and from a generous rainfall, engulfs it in a countless number of swallets, many of which are insignificant, whilst some of the larger have been opened by our exploring parties during the past few years, and followed through unimagined beauties to profound depths.