458 SUBTEERANEAN WATERS. 



these and other like computations, tlie water carried down into 

 the earth by capillary and larger conduits is wholly lost sight of, 

 and no thought is bestowed upon the supply for springs, for com- 

 mon and artesian wells, and for underground rivers, Hke those in 

 the great caves of Kentucky, which may gush up in fresh- water 

 currents at the bottom of the Caribbean Sea, or rise to the hght 

 of day in the far-off peninsula of Florida.* 



The progress of the emphatically modern science of geology 

 has corrected these erroneous views, because the observations on 

 which it depends have demonstrated not only the existence, but 

 the movement, of water in nearly all geological formations, have 

 collected evidence of the presence of large reservoirs at greater 

 or less depths beneath surfaces of almost every character, and 

 have investigated the rationale of the attendant phenomena.f 

 The distribution of these waters has been minutely studied with 

 reference to a great number of locahties, and though the actual 

 mode and rate of their vertical and horizontal transmission is 

 stUl involved in much obscurity, the laws which determine their 

 aggregation are so well understood, that, when the geology of a 

 given district is known, it is not difficult to determine at what 

 depth water will be reached by the borer, and to what height it 

 will rise. 



The same principles have been successfully applied to the dis- 



* In the low peninsula of Florida, riv^ers, which must have their sources in 

 mountains hundreds of miles distant, pour forth from the earth with a volume 

 sufficient to permit steamboats to ascend to their basins of eruption. In 

 January, 1857, a submarine fresh-water river burst from the bottom of the 

 sea not far from the southern extremity of the peninsula, and for a whole 

 month discharged a current not inferior in volume to the river Mississippi, or 

 eleven times the mean delivery of the Po, and more than six times that of the 

 Nile. We can explain this phenomenon only by supposing that the bed of 

 the sea was suddenly burst up by the hydrostatic upward pressure of the 

 water in a deep reservoir communicating with some great subterranean river 

 or receptacle in the mountains of Georgia or of Cuba, or perhaps even in the 

 valley of the Mississippi. — Thomassy, Essai^ur V Hydrologie. 



Late Southern journals inform us that the creek under the Natural Bridge 

 in Virginia has suddenly disappeared, being swallowed up by newly formed 

 ■fissures, of unknown depth, in its channel. It does not appear that an outlet 

 lor the waters thus absorbed has been discovered, and it is not improbable 

 that they are filling some underground cavity like that which supplied the 

 submarine river just mentioned. 



f See especially Stoppaiti, Corso di Oeologia, i., pp. 270, et aeq. 



