FORMATION OF THE CAVE. 
7 
corridors, can convey anything like an adequate idea of the place. 
After spending fifteen hours within its chambers, it is absolutely 
nauseating to read the descriptions which have been current in the 
letters of newspaper correspondents for a quarter of a century, 
and even the vigorous and picturesque language of Bayard Taylor 
becomes tame and commonplace when it attempts to describe this 
subterranean wonder of the world. 
How and when the cave was made, were the leading questions 
in the minds of the geologists. They do not believe that the cave 
was the immediate result of some violent upheaval of the strata, 
which left these vast crevices and chambers of which the cave is 
composed ; neither do they share the popular belief that the rapid 
and violent action of some subterranean stream of water has 
worn these deep channels through the limestone ; on the contrary, 
they find conclusive evidence that the same agencies are at work 
and the same ciianges in progress to-day that have been slowly, 
steadily and quietl}^ through vast periods of time, accomplishing 
the marvellous wonders that now astonish the beholder. The cave 
is wrought in the stratum known as the St. Louis limestone, which 
in some places reaches a thickness or depth of four hundred feet. 
This stone is dissolved whenever it is subjected to the influence of 
running or dripping water impregnated with carbonic acid gas. 
Water exposed to the air readily absorbs this gas, and surface water 
percolating through small fissures of the limestone, dissolves it. 
Another fact should be stated. When, during this process of so- 
lution, the water becomes thoroughly impregnated with lime, it 
loses its power to dissolve the stone. The following conditions, 
then, were essential to the productions of the cave, assuming what 
is not disputed by geologists, that the' place where the cave now is, 
was once nearly solid limestone. First, that there should be fis- 
sures in the strata, allowing the ingress of the surface ivater. Sec- 
ondly, there should be a place or places of exit for the water charged 
with limestone in solution. Without the latter, the water would 
become charged with lime, fill up the crevices, and the dissolving 
process would cease. These conditions are all present to-day, and 
have remained the same during the countless ages that have passed 
away while the work has been in progress. There have doubtless 
been times in the history of the cave, when, owing to a greater 
flow of water, the work has progressed more rapidly than at pres- 
ent, but that the results have been accomplished in the manner 
stated, rather than by the process of attrition by rapid currents of 
large volumes of water, seems to be the general opinion of scien- 
tific men. This theory is strengthened b}^ the fact that where the 
cave attains its greatest heights, and reaches its lowest depths, 
the dripping waters have never ceased their labors, and are busily 
at work to-day. In the Mammoth Dome, for instance — rarely 
seen by visitors, on account of the dangers and fatigue incident to 
the journey — where the chasm attains a height and depth of more 
