THE ORIGIN OF THE ST. PETER SANDSTONE 
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slowly, probably from the south. To the north, there was the 
Laurentian land area, on which igneous rocks were maturely 
weathered. Quartz, liberated from granitic rocks by the de- 
composition of associated silicate minerals, was broken to pieces, 
transported by streams, shaped somewhat, moved about by 
waves and currents in the sea, and deposited near the shore, 
as the sea advanced over the land. It is entirely possible that 
some sand was picked up by the wind from the beaches, trans- 
ported a little way inland, and later submerged beneath the 
advancing sea. In this way some eolian deposits may have been 
incorporated within the formation which is generally marine. 
Geological Laboratories, 
State University. 
