During the summer of 1915 some fulgurites were found near Sparta, Wisconsin, in a small sand knoll composed of residual quartz grains of the Potsdam formation, which is Upper Cambrian in age. The sand is fairly clean and of uniform character and is being reworked continually by the wind since there is only a scant covering of vegetation.
Proceedings of the Iowa Academy of Science
©1916 Iowa Academy of Science, Inc.
Shipton, W. D.
"A Note on Fulgurites from Sparta, Wisconsin,"
Proceedings of the Iowa Academy of Science, 23(1), 141-141.
Available at: https://scholarworks.uni.edu/pias/vol23/iss1/22