PREFACE. XI 
engraver and printer have done all that was asked of them, and the final responsi- 
bility for all defects and errors rests with me. In undertaking to state such a multi- 
plicity of facts as the present volume includes, it cannot be but that errors will be 
made. Some minor ones have already been discovered. I may, perhaps, justly ask 
that account shall be taken of the fact that I have been obliged to do this work in 
conjunction with the duties of my professorship in the State University, and also by 
the fact that I have been held within close limits as to expenditure by an appropria- 
tion that was designed for a much smaller volume. The style of execution adopted 
for maps and illustrations must be considered with this fact in view. It was required 
that the volume on economic geology should be published economically if at all. 
So far as I have treated of our mineral fields, I have aimed to give uncolored state- 
ments, statements that will prove equally fair to the buyers and the sellers of 
mineral lands. We are so accustomed to exaggeration and overstatement in the 
description of mineral wealth that when the sober truth is told, it sometimes seems 
an intentional disparagement. Time will undoubtedly show that some of our present 
estimates are too low and others will be found too high, but from errors of this sort, 
none are exempt. E. O. 
