MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 7 



have united in one tunnel. Following the left branch for a few yards a hall is found, in the floor of which is a pit 

 175 feet deep. The corresponding dome overhead is scarcely noticeable as such, for the surface of the ground is not 

 more than 30 or 40 feet distant. The end of the Long Eonte has been reached. 



In returning the passage through Fat Man's Misery is avoided, and nearly 2 miles of walking are saved by 

 climbing through a very steep, narrow, winding Corkscrew pass {t, Fig. 2), starting from the neighborhood of 

 Great Belief and terminating at the side of the Great Rotunda. The vertical ascent is about 140 feet. To even 

 stout-hearted mountaineers, if stout-bodied also, this Corkscrew is an intensified Fat Man's Misery, and upon them 

 it rarely fails to leave stroug and deep impressions, which may be of more kinds than one. 

 Dr. Newberry remarked on the geology of the region adjacent to the Mammoth Cave: 



" The limestoue beds of this high table-land are jointed in the manner common to rocks, apparently by some sort 

 of polarization, producing fissures which run in a north and south and an east and west direction. The plateau is 

 about 500 feet above the drainage, part of the drainage passing into the Green River and part into the Ohio. No streams 

 occur on the surface, and the drainage is quite gradual. At the angle between these two rivers several streams are 

 seen bursting out of the cliffs at various heights above the Ohio; they are, so to speak, subterranean sewers, repre- 

 senting the underground drainage of the country; at one point three such streams pouring out of the rock form 

 very beautiful cascades; aud near Sandusky a full-grown river flows out of the cliff of cavernous limestone. The 

 beds consist of Lower Carboniferous limestone, with sandy layers beneath. In the vicinity occur portions of the 

 great 'blue-grass region,' one of the oldest parts of the continent, once an extensive highland, forming an island 

 in the sea. Around this rims of sediment were deposited, consisting of sandstones and limestones; while, on the 

 other hand, the continuous process of erosion during the lapse of a vast period removed the material of the table-land 

 within, aud converted it into a broad depression or basin, the 'blue grass region,' above which the present plateau 

 of the encircling sediments now rises to a height of 500 feet. 



"The erosion of the joints in this plateau has resulted in the formation of the pits described by Mr. Stevens, but it 

 is probable that some of these may reach 200 or 300 feet below the Ohio and Green rivers.- There is evidence, from 

 borings in the Delta of the Mississippi, etc., that the continent was formerly more elevated, standing 500 to COO feet 

 higher at New Orleans than at present; the drainage was much freer, the Mississippi being a free- flowing; stream as 

 well as'the Ohio and other tributaries. Borings have been sunk in the present trough of the Ohio River to a depth of 

 over 100 feet below its present bottom without reaching the true bottom of the trough, the ancient bed of the river, 

 which is perhaps 100 to 200 feet farther down." 



The hydrography of Mammoth Cave may be understood by reference to the shaded portion of 

 the passages in the cave now filled with water or containing pools. 



Soon after entering the main cave one passes on the left a miniature cascade, which runs or 

 drips down into a basin called Wandering Willie's Spring, situated between the Standing Rocks 

 aL>d the Grand Arch. This rill probably comes more or less directly from the surface of the soil 

 above; and from the rill, as well as the pool, I took the water containing several species of infusoria, 

 while the pool was tenanted by the Crangonyx. It is possible, however, that the rill arises from 

 the collection of pools in the Labyrinth. Still farther on is Richardson's Spring, not men- 

 tioned in Mr. Hovey's book ; it is situated near Star Chamber, and in the pool, under stones, lives 

 the white eyeless Planarian worm, Dendrocoelum perccecum, while in the damp soil around and 

 under the stones were found beetles, Podurids, mites, and Myriopods. 



Another locality where the animals are in greatest abundance is the Labyrinth, in which is a 

 pool 12 feet deep. Near this is a brook, which we have called Shaler's Brook, It abounds in the 

 white eyeless Planarian worms, usually occurring on the under side of the pebbles in the bottom, 

 while a species of Chironomus and Crangonyx live in its waters. Near by is the Devil's Cooling 

 Tub. It was noticed here, as well as in other wet or watered localities, that no animals occurred 

 in the dry portions of the cave. Dampness or some degree of moisture is essential to their existence. 

 The cray fish aud blind fish for the most part, if not exclusively so, live in the River Styx and 

 the Dead Sea. The most accurate account of this region of the cave is that given by Mr. Hovey : 



On entering River Hall we followed a path skirting the edge of cliffs GO feet high and 100 feet long, embracing the 

 sullen waters to which the name of Dead Sea is given. Descending a flight of steps we came to a cascade, but a 

 litt le farther on, by some conjectured to be a re-appearance of the waterfall at the entrance of the cave, it precipitates 

 ftself iuto a funnel-shaped hollow in a massive mud-bank. On another visit, in 1881, we found a natural bed of 

 mushrooms growing here, a species of Agaricns, that has suggested the idea of a mushroom farm, similar to those at 

 Fn'pilon and M6ry, in France, whence many thousands of bushels are sent to market annually. 



The est i mated length of the Styx is 400 feet and its breadth about 40 feet. It was formerly crossed by boat before 

 the discovery of the Natural Bridge, whence Mat's party are hailing us with invitations to join their number and goon. 



Lake Lethe comes next ; a body of water about as large as the Styx, and, like it, once crossed only by boat. It is 

 now lower than formerly, being slowly filled with mud, and a narrow path runs along its margin, at the foot of cliffs 

 90 feet high, leading to a pontoon at the neck of the lake. Crossing this, we step upon a beach of the finest yellow 

 sand. This is the Great Walk, extending to Echo River, a distance of 500 yards, under a lofty ceiling mottled with 



