84 
THE SCIENTIST. 
pose that an eartliquake had occurred at a 
^•iveu point. The strength of the mo- 
tion of the shock would start equally in 
all directions, but coming through the 
rocks of the different periods they natur- 
ally must have taken different courses 
which were directed by the strength and 
situation of the rocks. It consequently 
does appear that the effects of this mo- 
tion came to the surface with different 
force at different places and tissuredihe 
rocks where it passed through. At some 
places the rocks were apparently entire- 
ly undisturbed, yet very much fractured 
notwithstanding no lead or zinc was 
found. The rocks were greai^y stained 
by peroxyde of iron showing that waters 
containing the same had percolated 
through them. This may have been the 
ellect of two or more original shocks or 
one where the force of motion was divi- 
ded and appeared at different places of 
the surface. The oscillating motion 
spread the force, and it must have be- 
come weaker and weaker the further it 
got away from the original point, conse- 
quently as they could not penetrate the 
lov/er stratifications again, they became 
shorter and shorter and finally only shat- 
tered the surface rocks, and in many in- 
stances the force became so weak that it 
could not fracture the rocks across a pre- 
vious fissure. So far I have explained 
how these fissures probably occur, and it 
remain? to find an explanation of their 
enormous widths. Maintaining the idea 
that the minerals were in solution and 
passed through the archaelan formation, 
1 will remark here, that whenever miner- 
als were found in these rocks, they were 
deposited in cavities which evidently 
were caused by the shifting or tlie break- 
ing of its stratification, while in other 
rocks the vein matter generally is close- 
ly connected with the walls and frequent- 
ly shows very plainly tliat the bed i-ock 
had been altered during the time when 
mineral was deposited, and in fact wliere 
it has been altered the most, the mineral 
deposits generally are the best. We know 
that under certain conditions minerals 
may be held in solution. Of course as 
this condition changes, such minerals 
will take other forms and likel}^ precipi- 
tate. As the rocks of the arcbaslan per- 
iod evidently had been subjected to 
great heat and are not very changeable 
by water, the solutions passing through 
them were changed but vei-y little, there- 
fore the mineral deposits therein were 
im\y caused by the less pressure and tem- 
perature ; but as soon as these soUuions 
passed through rocks which are suscepti- 
ble of dissolutions, the solutions would 
readily dissolve part of that rock and 
consequently would greatl}^ alter the ori- 
ginal condition of tlie solution. We 
know very well that, for instance, lime 
rock is very susceptible to dissolution by 
water, consequently minerals ma}^ be 
most expected between the lime rocks. 
It appears to me that such has taken 
place in the southern part of Missouri. 
The mineral waters naturally took their 
course through the fissures caused by an 
earthquake as before described. It 
is also natural, that where the force 
was the greatest, the fissure was the 
widest and consequently there the solu- 
tion could pass through the most readily. 
Originall}^, the fissures may not have 
been wider than six inclies, but the wa- 
ters gradually changed the rocks at some 
places to a width from two hundred to 
three hundred feet. It is also evident, 
that a great deal of alteration of the solu- 
tion took place in the lower strata, and 
consequentlj^ very little mineral was left 
in the water b}' the time it came near the 
surface, and therefore, at those places 
near the surface, as described above, 
very little or no mineral can be expected ; 
nevertheless, as it may be by various 
local causes, that the mineral solution 
may have been forced out of its original 
channel, it may have caused ore deposits 
under rock in place. Such places may 
have been struck by parties sinking 
