A cast of a pine cone composed of limonite was recently found in a gravel pit near Britt. Its composition and appearance suggest considerable antiquity. It is thought to belong to a Mesozoic or Tertiary Sequoia
Proceedings of the Iowa Academy of Science
©1924 Iowa Academy of Science, Inc.
Thomas, A. O.
"A Fossil Pine Cone from Drift of Northern Iowa,"
Proceedings of the Iowa Academy of Science, 31(1), 339-340.
Available at: https://scholarworks.uni.edu/pias/vol31/iss1/106