An Important Early Geological Survey of the Great Lakes Region.
This book encompasses the results of the Foster and Whitney survey regarding the geology of the vicinity of Lake Superior. This report was presented to the House of Representatives, following an 1847 commission to survey the land with a particular focus on copper mining.
Copper deposits in the Lake Superior region had been known to the Native Americans (copper mining deposits six thousand years old have been discovered) and appeared on the first geological map of North America, published in 1756. After treaties with the Indians in the 1830s and 1840s, public interest grew in exploiting these deposits. The state of Michigan attempted a survey, but the efforts were abandoned when the lead surveyor, Douglas Haughton, drowned during field work. In the meantime, Congress opened the lands to claims and sent what would become the first detailed survey of the region, originally lead by Charles Jackson. Jackson was dismissed for unclear reasons, and his assistants John Wells Foster and Josiah Whitney were put in charge. This was one of the earliest scientific publications of Josiah Whitney, an important figure in Californian history.
By 1850 the report would be ready. Foster and Whitney presented this report detailing their findings. They started with an introduction to the region's history of exploration, starting with the Raymbault and Jogue 1641 voyage. The rest of the work goes into great detail regarding the region, discussing not just the geology and mining capabilities, but the flora, fauna, soils, rivers, and much more.
This edition was followed by a Part II published in 1851 and concerned with the "iron region." In addition, an early detailed map of Lake Superior, showing the complete results of this survey, was also published. Despite the supposedly ten thousand copies of this book originally published, the volume, and in particular the maps included, are quite scarce today.
Maps
Four maps are included at the end of the present work. They include:
- Lac Superieur et autres Lieux ou sont let Missions des Peres de la Compagnie de Jesus Comprises sous le nom D'Outaouacs.
- This is a reproduction of a 1672 Jesuit map of Lake Superior, which was an important early map of the region. The map shows "Lac Tracy ou Superieur" along with parts of other Great Lakes. The map is impressively detailed for the time, naming many features, settlements, and more.
- Geological Map of Isle Royale
- This is almost certainly the earliest geological map of the island to delineate the geology correctly. Three Silurian units are denoted, a sandstone, a conglomerate, and a basic igneous unit. In addition, early mines are denoted. The map accurately shows the southeast dipping strata which define the island. The system is part of a syncline generated by two faults, the second of which underlies the Keweenaw Peninsula.
- Geological Map of Keweenaw Point
- This is another remarkable map showing features similar to the Isle Royale map. In the north of the peninsula, we see the same lithologies as on the island; this is the other limb of the syncline. To the south, bounded by what we know to be a northward dipping thrust fault, lies younger sediments, these are also named as Silurian in age on the map. Two further units are introduced, a "chlorite" and a "jasper" unit.
- Geological Map of the District Between Portage Lake and Montreal River
- This map covers a larger land area than the previous two maps and shows a slightly more complicated area. The new lithologies here are some metamorphic rocks and a granite. A great early reference is made to the "Azoic," a long-outdated name for the Pre-Cambrian, when life was not known to exist before 540 million years ago. Interestingly enough, it was a discovery in this area of northern Minnesota and southern Ontario on the shores of Lake Superior which would prove that life did indeed exist in the Archean.