In all the caves are to be found either inexhaustible springs of clear, pure, cold water, or streams inhabited by shrimps and fishes. No one can tell whence they come or where they go. All currents of water are subterraneous. Not a river is to be found on the surface; not even the smallest of streamlets, where the birds of the air, or the wild beasts of the forests, can allay their thirst during the dry season. The plants, if there are no chinks or crevices in the stony soil through which their roots can penetrate and seek the life-sustaining fluid below, wither and die. It is a curious sight that presented by the roots of the trees, growing on the precipituous[TN-1] brinks of the _senotes_, in their search for water. They go down and down, even a hundred feet, until they reach the liquid surface, from where they suck up the fluid to aliment the body of the tree. They seem like many cables and ropes stretched all round the sides of the well; and, in fact, serves as such to some of the most daring of the natives, to ascend or descend to enjoy a refreshing bath. These _senotes_ are immense circular holes, the diameter of which varies from 50 to 500 feet, with perpendicular walls from 50 to 150 feet deep. These holes might be supposed to have served as ducts for the subterranean gases at the time of the upheaval of the country. Now they generally contain water. In some, the current is easily noticeable; many are completely dry; whilst others contain thermal mineral water, emitting at times strong sulphurous odor and vapor. Many strange stories are told by the aborigines concerning the properties possessed by the water in certain senotes, and the strange phenomena that takes place in others. In one, for example, you are warned to approach the water walking backward, and to breathe very softly, otherwise it becomes turbid and unfit for drinking until it has settled and become clear again. In another you are told not to speak above a whisper, for if any one raises the voice the tranquil surface of the water immediately becomes agitated, and soon assumes the appearance of boiling; even its level raises. These and many other things are told in connection with the caves and senotes; and we find them mentioned in the writings of the chroniclers and historians from the time of the Spanish conquest.