Geology of indiana, §:c. 138 
fine chalcedony, and sometimes the interior was the same sub- 
stance, in the form of balls; all these were sometimes com- 
bined, forming agates of great beauty. 
Carbonate of lime, crystallized, is sometimes found; and 
many of the caves afford fine stalactites. 
There is a large cave near Corydon, celebrated for the pro- 
duction of sulphate of magnesia, or Epsom salts. It has been 
explored for the distance of several miles. When it was first 
discovered, the bottom, in many places, was covered to the 
depth of several inches, with pure, brilliant, needle-shaped 
crystals of sulphate of magnesia. By some mysterious process 
of nature, or rather of Divine benevolence, the production of 
this useful salt is continually going on. This cave also produ- 
ces some other salts in small quantities: nitrate of lime, nitrate 
of magnesia, sulphate of lime, &c. oe 
ere the basis of the country is limestone, the waters 
always take up a great quantity of lime, and some of them pos- 
Sess great petrifying powers. I saw many specimens of petri- 
factions: a tuft of moss, the form perfectly preserved ; leaves, 
bark, and branches of trees; insects, and many others. 
Many of the springs are strongly impregnated with sulphur, 
and some of them are saturated with sulphuretted hydrogen. 
I found the opinion universally prevalent among the people of 
this state, that the first appearance of these sulphur springs 
Was immediately subsequent to the earthquakes of 1812. They 
say, that then new springs, impregnated with sulphur, broke 
out, and the waters of some old springs, for the first time, gave 
indications of this mineral. A sensible farmer, who has a large 
sulphur fountain, boiling up from the bottom of a river near 
tS bank, assured me, that there was no trace of this spring 
until after the period to which I have alluded. He could 
“ve no interest in deceiving me; and if he did deceive me, 
his conduct could originate only in that love of the marvellous 
Which is so characteristic of the human mind. He, moreover, 
orared me that the « water had been growing weaker, (to 
"8e his phrase) ever since its first appearance.” Ihave room 
only to mention, among the minerals of Indiana, many varieties 
clay, ochres, gypsum, alabaster, muriat of soda, (very com- 
mon,) iton ore, and antimony. 
