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Authors

J. A. Udden

Document Type

Research

Abstract

In Jefferson County the Pella beds of the Saint Louis formation have a thickness of about twenty feet. They consist of heavy ledges of calcareous limestones, interbedded with seams of marly shales, the latter being best developed in the upper part of the section. The several seams and ledges appear quite persistent and some have been identified at different points a few miles apart. They have evidently been laid down at some considerable distance from the shore. Occasionally there are ledges of limestone which are very fine-grained, almost lithographic in texture. Here as elsewhere in the south part of the state, the fauna of the formation is meager in species but quite prolific in individuals. Pugnax ottumwa, Spirifer keokuk, Zaphrentis pallaensis, Anisotrypa fistulosa, and stems of crinoids appear everywhere, especially in the marls. This has long been known.

Publication Date

1901

Journal Title

Proceedings of the Iowa Academy of Sciences

Volume

9

Issue

1

First Page

120

Last Page

120

Copyright

© Copyright 1901 by the Iowa Academy of Science, Inc.

Language

en

File Format

application/pdf

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