David Dale Owen made note more than fifty years ago of the multitudes of fragmentary specimens of Asaphus iowensis in an exposure at the junction of Otter Creek with the Turkey River at Elgin, Iowa. From then on, that locality has been classic trilobite territory. The most abundant species to be found entire there now, if good trilobites can be said to be abundant anywhere, is Nileus vigilans, which occurs both enrolled and more or less straightened in form.
Proceedings of the Iowa Academy of Science
©1903 Iowa Academy of Science, Inc.
Finch, G. E.
"Notes on the Position of the Individuals in a Group of Nileus vigilans Found at Elgin, Iowa,"
Proceedings of the Iowa Academy of Science, 11(1), 179-181.
Available at: https://scholarworks.uni.edu/pias/vol11/iss1/26