ROCK FORMATIONS AND PRE-GLACIAL HISTORY 



Photo by Michigan Deparlmcnt of Comervation 



PLATE 1.— "PICTURED ROCKS" RAMPART OF CAMBRIAN 

 SANDSTONE 



SOUTH SHORE OF LAKE SUPERIOR; NIPISSING AND MODERN LAKES. 



gray and white sandstone, rising majestically two hundred 

 feet above Lake Superior, facing the moat of the Superior 

 basin. It is the most battlcmented of all the ramparts, and on 

 it Nature has painted her "Pictured Rocks" and carved archi- 

 tectural designs that delight and awe the beholder. We can 

 follow this Cambrian rampart from Sault Stc. Marie to the 

 eastern half of the Keweenaw Peninsula,''" and from east of 

 Marquette we can trace it southward into south-central 

 "Wisconsin, where it swings westward around the old, igneous 

 land-mass of central Wisconsin. Short streams entering Lake 

 Superior from the south leap over the edges of the sandstone 



*The sandstone in the basin of Keweenaw Bay, which forms tlie rampart alonj; its shore 

 and east nearly to Marquette, may be of pre-Cambrian age. (Editor.) 



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