Encyclopedia Dubuque
"Encyclopedia Dubuque is the online authority for all things Dubuque, written by the people who know the city best.”
Marshall Cohen—researcher and producer, CNN
Affiliated with the Local History Network of the State Historical Society of Iowa, and the Iowa Museum Association.
JAGNOW, David
JAGNOW, David. (Dubuque, IA- ). Jagnow was one of two discoverers of Coldwater Cave believed to be the largest cave ever discovered in Iowa. Water inside the cave remains a constant 47 degrees with the air temperature only a few degrees warmer.
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Source:
Iowa Underground: A Guide to the State's Subterranean Treasures, p. 86 - Google Books Result books.google.com/books?isbn=1931599394
Oneota Flow: The Upper Iowa River and Its People, p. 74 74 - Google Books Result books.google.com/books?isbn=1587298368