Various, Scientific American Supplement…
“ Perhaps no other portion of the earth's surface is so rich in mineral resources as that which has been covered by these observations, and nowhere else is to be found as great a variety of ore deposits, or those which illustrate as well their mode of formation. This is so true that it maybe said without exaggeration that no one can intelligently discuss the questions that have been raised in regard to the origin and mode of formation of ore bodies without transversing and studying the great mining belt of our Western States and Territories. ”
