FORMATION OF THE CAVE. 
9 
to correct a popular error concerning the formation of the beauti- 
ful structures that adorn the ceilings of some portions of the cave. 
In the dryer localities, where the floors are dusty and everything 
indicates the prolonged absence of moisture, the ceiling is covered 
with a white efflorescence that displays itself in all manner of 
beautiful shapes. It requires no stretch of the imagination to dis- 
cover among these, the perfect forms of man}^ flowers. The lily 
form prevails, and the ceilings of many of the chambers are cov- 
ered with this beautiful stucco work, surpassing in delicacy and 
purity the most beautiful workmanship of man. These are not 
produced, as many suppose, by the dripping of water, and the 
gradual deposit of sulphate of lime upon the outer portions. The 
stalactite is formed in this manner, but these are neither stalacti- 
forrn, nor are they produced in a similar way. Dripping water 
is the agency that forms the stalactite, while the efflorescence 
in the dryer portions of the cave cannot take place where there is 
much moisture. The growth of these beautiful forms is from 
within, and the outer extremities are produced first. They are 
the result of a sweating process in the limestone that forces the 
delicate filaments of which they are composed through the pores 
upon the surface of the rock, their beautiful curved forms result- 
ing from unequal pressure at the base, or friction in the apertures 
through which they are forced. Mr. L. S. Burbank, of Lowell, 
Mass., has kindly furnished us with the following abstract of his 
opinions upon this interesting subject. 
‘The rosettes, wreaths, and other curved fibrous forms of g 3 fl 3 - 
sum, in the Mammoth Cave, occur only in particular strata of the 
limestone which do not appear in the first part of the long route. 
Their formation may be explained in this way : that portion of 
the rock where they are found consists of carbonate of lime, with 
some impurities, and contained originally the sulphide of iron, or 
iron p3uites, disseminated in small grains or ciystals, and also in 
rounded nodules or concretions, sometimes of considerable size. 
By exposure to air and moisture, ox3^gen unites with both the 
sulphur and the iron, producing sulphuric acid and oxide of iron, 
which combined, form a sulphate of iron. Then a double de- 
composition takes place ; the sulphuric acid unites with the lime 
to form the gypsum ; the carbonic acid of the limestone combines 
with the oxide of iron, forming a carbonate of iron, and this, on 
further exposure, parts with the carbonic acid, and leaves the 
brown coating of oxide, which is seen in man3" places on the sur- 
face of the rock. 
The gypsum is thus constantly forming in the rock, and, being 
soluble, is carried b3^ the water to the exposed surface where it 
cry^stallizes. 
The crystals appear to grow out from the rock b3" additions from 
beneath, which continue to push the ends first formed, and if these 
do not become attached to other parts of the rock, straight needle- 
