The map depicts the different kinds of rocks emerging on North America's surface. Each kind of rock is represented by a conventional colour, referring to the geological period. It also shows the eruptive and inactive volcanoes and the different kinds of eruptive rocks. The map relies on E. Deckert's one, based on "Geological map of North America" realized by B. Willis e G. Stose. The map is one of the tables made by the TCI Cartographic Office for the Italian Encyclopedia of Giovanni Treccani Institute
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<bdi><a href="https://en.wikipedia.org/wiki/en:Touring_Club_Italiano" class="extiw" title="w:en:Touring Club Italiano"><span title="large publisher">Touring Club Italiano</span></a>
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