HaAwortu. | Detailed Geology. 93 
strata by taking cognizance of well-established changes within 
the stratified rocks themselves. A total absence of what may 
be called the hot-water or fumarole_minerals within the entire 
zine fields is a fact which should not be overlooked, and it 
grows in importance the more it is considered. If the mild 
disturbances were accompanied by deep fissuring, that is, pro- 
duction of fissures which extend far below the surface of 
underlying crystalline rocks, how can we explain the total 
absence of hot water minerals? It is true we find a little 
quartz here and there, and a great mass of secondary flint or 
chert which has been deposited from solution. But it is 
further true that we have a total absence of every other 
mineral recognized as usually associated with quartz pro- 
duced by ascending hot waters from great depths. It may 
be, therefore, that the large amount of secondary flint shows 
us how the almost insignificant amount of quartz could have 
originated, namely, from cold solutions. 
By way of summary it may be stated, therefore, that the 
most apparent cause of the very unusual fracturing in the 
Galena-Joplin district is the unusual amount of flint associa- 
ted with the limestone, in connection with earth movements 
which produced the Ozark dome with its gently sloping sides. 
This earth movement required a stretching of the stratified 
rocks, which was brought about by breaking them asunder 
in many places so as to produce the extra surface measure- 
ments. Such yieldings occurred most abundantly where 
fractures already existed, that is, where flint is most abun- 
dant, and the stratified formations were thus pulled asunder 
and stretched, relieving existing tension. This permitted an 
extra influx of surface water which dissolved large portions of 
the interbedded limestone, probably intensifying the disturb- 
ances already produced by causing unequal vertical contrac- 
tion, thereby intensifying the fissures, greatly enlarging some 
of them, and producing numerous lesser vertical displace- 
ments or faults. 
Ground Water. 
One of the most important matters connected with mining 
operations is that of water. This subject naturally divides 
itself into three classes: First, water to be used on the sur- 
