We come in contact with rough edges on every side, while narrow passes almost obstruct our progress, when suddenly we are ushered into _El Cathedro_, forty feet in height, and nearly the same in length, with a variable width of twenty feet. Here is found the basin of holy water, blessed by no earthly priest, fed by a fountain whose innermost recesses have never been penetrated, or measureless depths fathomed. The palace halls of princely dwellings, decked with costly gems of priceless value, shine with no more dazzling luster than the icicle-shaped pendants of snowy whiteness hanging from the arch and sides of this remarkable underground temple. The stalactites in many places form solid columns of transparent crystals, which meet the stalagmites, and extend to the earth. Oyster-shells and sea-urchins of immense size are found imbedded in the rocks, which demonstrate that this has been the home of the restless sea, where old Neptune combed his "hoary locks," and beat his foaming billows. To enter this subterranean cavern seems like standing on the brink of a volcano, our only hope of escape, being a fickle flame extinguished by a breath, looking into the domains of futurity, not knowing how soon we might be called upon to try its realities. No one can conceive the period of time which has been consumed in the production of this remarkable formation--a drop of water, containing the fractional part of a grain of lime, leaving an imperceptible deposit in its downward course, thus forming the stalactites and stalagmites of fantastic forms and delicate proportions, which the ingenuity of no human hand, however skillful, can imitate. A kind of awe-inspiring sensation seizes our minds while surrounded by the oppressive stillness in these depths, where mighty forces are fulfilling their great purposes in producing mountains by infinitesimal accessions.