I might mention the demonstrated antiquity of the bosses of stalagmite in Kent's Cavern at Torquay, and from it argue the immense age of the great masses of stalagmite in the Mendip Caves, but, recognising the variable rate of deposit of the carbonate of lime in different caverns, and indeed in different parts of the same cavern, no useful purpose would be served thereby. The huge Beehive of Lamb's Lair at Harptree, the large boss in the first great chamber at Wookey Hole, Gough's "Niagara" at Cheddar, the tall and slender pillars in Cox's Cave at Cheddar, and the taller "Sentinel" pillar at Wookey Hole, all demand for their formation a prodigious length of time, which it is but folly to attempt to compute with our present information. Certainly many thousands of years are required for some of them, and it should be remembered that we have then arrived merely at the time when the floor upon which they stand had received its final form, the action of running water having ceased.[2] Who can doubt then, that, as we stand in the great waterways of the profound depths of our hills, we are looking upon scenes which have varied little since remote ages, and that in some form or other these waterways played an important part in the degradation of the earlier and loftier Mendip range?
It is worthy of remark in this connection that the veteran M. Martel, commenting upon the caverns of Mendip, says, "In consequence of the existence, on the flanks of the Mendip Hills, of deposits of Triassic Dolomitic Conglomerate (Keuper) of Rhaetian beds, and of possibly Glacial alluvia, unconformably on the Carboniferous Limestone, the outflow of the water in the risings operates in three ways: (A) by large fissures in the Limestone itself, when it flows out freely, as at Cheddar; (B) through the crevices in the Dolomitic Conglomerate (the Axe at Wookey Hole, etc.); (C) where the outlet of the water from the Limestone is hidden by alluvia (St. Andrews Well, at Wells). The consequence of this arrangement is that it will be possible—notably at Wookey Hole, when the explorations now going on have enlarged the new galleries recently found—to ascertain whether the Dolomitic Conglomerate is there shown in long beds of ancient shores, regularly superposed on the Limestone, or rather accumulated in filled-up pockets, in hollows pre-existing in the Limestone; that is to say, there will be a material verification of Mr. Balch's hypothesis (already outlined by Boyd Dawkins in 1874) of the very ancient excavation of certain caves of the Mendip Hills, even before the Keuper period. The lie of the Conglomerate under the vaulted roofs of Wookey Hole appeared to me to favour this idea. And it is necessary to wait till formal proofs have been gathered together here, that caves were hollowed out there before the Trias. I recall, on this subject, that long ago I concluded, with Messrs. De Launey, Van den Broeck, Boule, etc., that the formation of caves could commence in the most distant geological epochs, and that the pockets of phosphorites, among others at Quercy and the Albanets of Couvin (Belgium), testify to caves or abysses of at least Eocene times."
H. E. B.
[CAVE EXPLORING AS A SPORT]
We are called a nation of sportsmen; yet the first criticism we level against any new sport, not our own, is the question, usually unanswerable and always irrelevant, What is the use of it? One may then, with a certain show of propriety, point out that cave exploring is a sport not entirely lacking in utilitarian or scientific objects. It belongs, in fact, to that large class which originated as something else than mere pastime. Mountaineering and hunting are typical representatives of that class. The earliest mountaineers were geographers. Cave exploring was first of all taken up as a branch of archæological and palæontological research, and then as a general inquiry into the physical nature of caves. But a science that has discovery as its principal object, and hardships and adventure as its natural concomitants, is bound to attract as many sportsmen as scientists. The geographical might be called the sporting sciences. And so there are now many ardent cave explorers who would blush to be called speleologists, their sole motive being the enjoyment of the game, and scientific results purely a by-product. Thus the science of caves has given birth to a sport that subserves its aims in the same irregular way as rock-climbing and peak-bagging subserve the aims of geography, geology, meteorology, and other sciences.
Speleology itself is, comparatively, a new science. Cave hunting, the search for human and animal remains, has been an important bypath of scientific investigation since the days of Dean Buckland and the discoveries recorded in Reliquiæ Diluvianæ, 1823. Professor Boyd Dawkins has in recent decades done still more valuable work for palæontology. Speleology is a word of both wider and narrower meaning; in the widest sense covering all kinds of knowledge about caves, their geography, geology, hydrology, their fauna, their palæontology. But most speleologists confine their attention to the physical characteristics of caves. This side of the inquiry has practical utilities. At Vaucluse, for instance, near Avignon, M. Bouvier in 1878 explored the channels of a gigantic siphon that carries the waters of an inaccessible reservoir into the Fontaine de Vaucluse, a famous "rising." His object was partly scientific, and partly to determine the nature of this permanent source, so as to utilise its waters to regulate the level of the Sorgue, to extend the irrigation system of the neighbourhood, and to secure water-power for manufacturing purposes. The Katavothra of Pod-Stenami were enlarged by an enterprising engineer, and protected by iron gratings, after their subterranean exits had been explored, and so utilised to regulate the drainage of the marshy plains of Laibach, and to prevent periodical inundations. In our own country, underground exploration has brought to light valuable water-supplies, and enabled us to safeguard the public interests by pointing out sources of pollution. Caves are most abundant in the districts where those great fissures known as rakes occur, which are rich in minerals, especially lead, calamine, copper, gypsum, and fluor-spar. During the short period in which cave work has been taken up as a sport, discoveries have been made, which of course it is impossible to particularise, that may be the source of considerable profit in the future.
The majority of those engaged in this physical exploration of caves are French. France possesses a Société de Spéléologie, the secretary of which, Monsieur E. A. Martel, author of Les Abîmes, is a most indefatigable and courageous explorer, and the man who has made the science an important and a living one. But M. Martel himself awards the title of "créateur de la spéléologie" to a forgotten predecessor, Dr. Adolphe Schmidl, who published Die Grotten und Höhlen von Adelsberg, in 1854. In this country, although such brilliant discoveries have been made of extinct animals and prehistoric relics of humanity, cave exploring of this kind is a new pursuit. M. Martel says, in Irlande et Cavernes Anglaises, 1897: "In short, the underground of the calcareous regions of the British Isles may be considered as being, topographically, very insufficiently known; this is the conviction impressed on me by my own researches in 1893." Something has been accomplished since that date. Two or three clubs, consisting chiefly of climbers, and a few speleologists working independently, have effected a thorough examination of the great caverns of the Peak, the extraordinary system of underground waters, huge cavities, and profound abysses in the West Riding, and the beautiful caverns of Somerset. But the ground that remains unexplored, the opportunities for adventure and the possibilities of discovery are such as may probably astonish those people who think there is nothing of the sort left in Old England.
Caves are formed in calcareous strata by the chemical action of water laden with carbonic acid, and by the mechanical action of streams. In consequence of the original structure of the Limestone, the joints of which run at right angles to the bedding planes, these eroded hollows have two dominant forms: the vertical pot, swallet, or hole, produced by the widening of a master-joint; and the horizontal water-channel, running in the same direction as the line of stratification. But the strata being commonly tilted, these pits and abysses are often a long way out of the vertical, and the caverns that follow the strata very steep. Many of these ancient watercourses are now dry, but others are still traversed by streams, and present the explorer with most formidable obstacles. The complete exploration of any cave system would involve the tracing out of all its passages from the point where the stream or streams enter the earth to the point of exit. But I know not a single instance where such a task has been worked out in its entirety. In many cases the streams enter the ground merely as small rivulets, and begin to excavate passages practicable to man only at a considerable depth. "Siphons," or traps, as they ought to be called, complete or partial chokes, and a variety of other causes, may put insuperable obstacles in the explorer's way.