The regions here referred to enjoy the advantage, and at the same time suffer the disadvantage, of being comparatively little known to the ever restless tide of tourists who naturally hail with pleasure the announcement that some easily accessible, and thoroughly charming spot, has escaped their attention altogether, with a marvelous store of attractions which are both extremely old and wholly new. Each of these regions has a peculiar geological history not repeated in any other portions of the earth's surface: each is blessed with its own peculiar style of beautiful scenery: and each vies with the other and all the world besides for the supremacy of its truly wonderful caves. Yet it should be well understood that the claims are not based on an unworthy spirit of rivalry, nor any desire to deny the greatness and beauty of already famous members of the Cave family. It is simply an announcement that the family is much larger than has been generally supposed, and the more recently presented members worthy of the full measure of distinguished honors. The geological authorities of both states have for many years mentioned the beauty and importance of these regions, and urged their claims to public attention, but have been prevented, by the pressure of other duties, from giving to the caves such careful study and full reports as they deserve, as it would have been a pleasure to give, and as has been possible in states of less extent where the general work of the department is more advanced, and the volume of tourist travel created an early demand for scientific explanation. Without any great difficulty we can understand the process of cave excavation by the action of percolating acidulated water on the limestone, and its subsequent removal as the volume of surface drainage diverted to the new channel gradually increased. But it is not so easy to offer a reason for the varied forms with which the caves are afterwards decorated. Why is it the charmed waters do not leave the evidence of their slow passage only in plain surfaces of varying widths, and the stalactites and stalagmites whose formation we can readily account for? And why do not the deposits take the same forms in all caves with only such variations as would naturally result from differences in topography? The law is written, but in unfamiliar characters that render our reading slow and uncertain. Yet it is conspicuously noticeable that those caves showing the most delicately fragile and wonderfully varied forms of decoration are those traversed by the most sweeping and changeable, or even reversible, currents of air; which might lead to the conclusion that the moisture is sprayed or converted into a light, misty vapor, and then deposited in exactly the same manner as the beautiful frost-work at Niagara: the direction and force of the current determining the location of the frail deposits.