Cone-in-cone is a term which has been applied more or less widely to a peculiar structure often found in beds of shale. Ordinarily it appears in thin sheets or layers, from three to six inches in thickness. The bands have a more or less well marked columnar structure, each column being about half an inch in diameter and composed of a series of small conical segments set one within another. In general appearance fragments resemble the familiar coral Lithostrotion.
Proceedings of the Iowa Academy of Sciences
©1895 Iowa Academy of Science, Inc.
Keyes, Charles R.
"Note on the Nature of Cone-in-Cone,"
Proceedings of the Iowa Academy of Science, 3(1), 75-76.
Available at: https://scholarworks.uni.edu/pias/vol3/iss1/21