4 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



tera by Baron Osten Sacken, aad the only Psocidse found have been described, so far as they 

 could be, by Dr. Hagen. 



In 1880 I visited the New Market and Luray caverns. Mr. H. G-. Hubbard has kindly loaned 

 me many of the specimens which he collected in Mammoth Cave. The entire collection of cave 

 insects, excepting some of the duplicates, embracing the types obtained by Mr. Sanborn and 

 myself while attached to the Kentucky geological survey, have been placed in the Museum of 

 Comparative Zoology at Cambridge, Massachusetts. 



I. DESCRIPTION OF THE BETTER-KNOWN CAVES. 

 MAMMOTH CAVE. 



As Mammoth Cave is the largest and most frequented, and was the first known to contain eye« 

 less animals, we will first briefly describe this great cavern, simply dwelling on those points which 

 are of interest from a biological point of view. One can form little idea of the general geological 

 relations of this cave from a few visits, especially when busied with the search for cave animals; 

 and we are indebted to the Kentucky geological reports, containing accounts by Professors Owen 

 and Shaler, also to an excellent paper by Mr. W. Le Conte-Stevens, 1 and the carefully -prepared 

 work of Rev. H. C. Hoveyou "^Celebrated American Caverns," who has given the results of much 

 time spent in exploration, and has taken, with more care than any one else, the temperatures of 

 this 1 and other caves. By consulting Mr. Hovey's map of the cave 2 and reading Mr. Stevens's 

 condensed account, aided by his sketches, we can obtain a fair idea of the topography of the cave, 

 embracing the dry and damp portions; i. e., those portions not deserted, and those most frequented 

 by the animals of the caves. 



Mammoth Cave is situated in latitude 37° 14' N., and longitude 86° 12' W., in Edmondson 

 county, Kentucky. It is the largest out of five hundred caverns estimated to exist in this county. 

 These caves are excavated in the subcarboniferous limestone, covering a more or less elevated 

 area, estimated to be 8,000 square miles in extent, and varying in thickness from 10 to 300 or 400 

 feet. This plateau is so honey-combed, that the drainage is almost entirely subterranean. The 

 general features of this limestone table-land are paralleled by those of the less extensive Carniolan 

 caves, described as follows, in G-eikie's Elementary Lessons in Physical Geography (p. 246-247).. 



One of the most remarkable examples of this kind of sceuery is tliat of the Karst, in Carniola, on the flanks of 

 the Julian Alps. It is a table-land of limestone, so full of holes as to resemble a sponge. All the rain which falls 

 upon it is at once swallowed up and disappears in underground channels, where, as it rushes among the rocks, it can 

 be heard even from the surface. Some of the holes which open upon the surface lead downward for several hundred 

 feet. Some turn aside and pass into tunnels, in which the collected waters move along as large and rapid subter- 

 ranean rivers, either gushing out like the Timao at the outer edge of the table-land, or actually passing for some 

 distance beyond the shore, and finding an outlet below the sea. Here and there the labyrinths of the honey-combed 

 rock expand into a vast chamber with stalactites of snowy crystalline lime hanging from the roof or connecting it 

 by massive pillars and partitions with the floor. Such is the famous grotto of Adelsberg near Trieste — a series of 

 caverns and passages with a river running across them." 



Stevens states that the subcarboniferous limestone in which the Mammoth Cave is situated is 

 overlaid with a thin stratum, mostly of sandstone, which is pierced by thousands of sink-holes 

 through which the surface drainage is carried down into limestone fissures and thus to the general 

 drainage level of the Green River. " This stream passes at the distance of less than a mile from 

 the Cave Hotel, the floor of the latter being 312 feet above the water and 118 feet above the mouth 

 of the cave." He adds : " The rate of erosion in the Mammoth Cave has been variable. The older 

 parts are perfectly dry, and entirely free from stalagmitic deposits, indicating rapid erosion, fol- 

 lowed by elevation, so as to deviate the water completely into other channels. In the newer parts 

 the water is still dripping from the surface above, and depositing stalactites and stalagmites." It 

 is in the newer damper parts, as well as in or near the subterranean streams and pools of this and 

 most if not all the other caves that the animal life mostly congregates. It will be seen that the 

 caves have frequent passages communicating with the upper world, and it will also be seen how 



1 For the titles of these articles see Chapter X, Bibliography. 



2 Kindly loaned by the publishers, Robert Clarke & Co., Cincinnati. 



