Excerpt from An Historical Sketch of the Lake Superior Region to Cambrian Time The ancient formations 'south of Lake Superior may be grouped into five great div

Excerpt from The Geology of the Lake Superior Region Rates of royalty and value of ore in the ground. Origin of the ores of the Lake Superior pre-cambrian sedim

Excerpt from Lake Superior Region The accounts of the mineral ranges in this volume contain the details of the succession. Here only a very general summary is a