A HISTORY OF DERBYSHIRE Some of the caverns at Matlock Bath are well worth a visit, but it is unnecessary to enter into any details concerning them, as they are com- binations of watercourses and old lead mines. The so-called caverns on the High Tor are roofless for the most part and are probably joints which have been enlarged by the action of water. The fissure called the Fern Cave runs north-north-west and is nearly parallel to the precipice of the High Tor. It is about 600 feet long, 150 feet deep, and in places reaches a width of 2 feet. It probably once extended further in the direction of Matlock Bridge. The eastern wall of the fissure pro- produced forms the face of the present cliff which bounds the valley of the Derwent. The Roman Cavern is a smaller fissure which runs nearly parallel to the strike and to the boundary between the limestone of the High Tor and the shales and grits of Riber Hill. WARM SPRINGS Many parts of the limestone district are destitute of water because of the readiness with which the surface waters make their way under- ground. Springs on the limestone hills are only present where there are beds of impervious rock as Clay and Toadstone. These springs issue from the top of the Clay or Toadstone along its line of outcrop. Several springs flow from the top of the bedded tuff near Grange Mill. Dunsley Spring which runs down into the Via Gellia, several springs near Tadding- ton, and that which supplies Tideswell with water flow from the upper surface of Toadstone beds. Many of the springs are warm, or at least tepid. The most noted are at Buxton, Matlock and Bakewell. The temperature at St. Ann's Well at Buxton is 81 F. The water is remarkable for the amount of free nitrogen dissolved in it. Another spring supplies the tepid swimming bath. The temperature of the warm springs at Matlock Bath is 68 F. They supply the Fountain Swmming Baths and smaller baths at the New Bath and Royal Hotels. An analysis of the spring at the Fountain Baths was made by Dr. Dupre. It contains Grains per gallon Chloride of sodium 4'57 Sulphate of magnesia 9-73 Sulphate of calcium 2*04 Carbonate of calcium I4'68 Silica 071 Total 373 Organic matter, traces of alumina, minute traces of potassium, lithium and strontium and loss . . . 1-03 Total dry residue 3276 and a small quantity of free carbonic acid. The old swimming bath at Bakewell is supplied at a temperature of about 60 F. 10
