APPENDIX—GEOLOGICAL SURVEY. 
433 
The sides of these channels or pipes seem sometimes almost 
vitrified, as though the water passing through them had a very 
high temperature, and continued passing through for a great 
length of time. All things considered it would seem- that the 
passage of this water (if it was water) was from below up¬ 
ward in the shape of thermal waters. 
It may be premature, with the limited information in our 
possession, to attempt to explain the origin of this class of phe¬ 
nomena, or its relation to other classes of phenomena con¬ 
nected with our mineral veins; but it certainly justifies the 
presumption that it belongs to a class of phenomena which 
will, when the details are worked out and classified, establish 
the dependence of our mineral veins upon the physical forces 
that have acted upon these mineral strata from below. And cer¬ 
tainly it justifies the conclusion that these are evidences and 
manifestations of mechanical forces (whatever may have been 
their form) that have caused the physical disturbance along 
those lines already referred to and with which our mineral 
strata are connected. 
It may not be in just the right place, but I would like to in¬ 
troduce here two or three pages of theoretical considerations in 
connection with the phenomena already presented. It will en¬ 
able us the better to understand this, and prepare our minds for 
further investigations. 
The evidences of mechanical and chemical forces acting along 
these lines of elevation and belts of mineral land are so mani¬ 
fold and convincing, that no scientific man will question their 
existence. And though it may be difficult to demonstrate that 
these forces were generated by internal heat, yet all classes of 
phenomena point in this direction. In the absence of demon¬ 
stration or positive proof, let us arrange the information in our 
possession with a view to the explanation of these phenomena. 
The natural position or lay of the strata through this part of 
the state, as represented by my map, is a gentle elevation to 
the north, consequently a gentle dip or declivity to the south. 
Hence we find that the series of stratified rocks is gradually 
growing thinner from the south to the north, until the lowest 
