New details on the Precambrian rhyolites and Upper Cambrian sedimentary rocks indicate that the tectonic style of the St. Francois Mountain area most probably can be compared with plateau (cratonic) areas and not with orogenic areas. The porphyritic rocks are in much the same position as when they formed. Depositional and lithologic features of the sediments across the pronounced Precambrian topographic relief suggest the sediments were deposited around and on the Precambrian knobs without later horizontal movements.

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