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Authors

Charles Keyes

Document Type

Research

Abstract

Attention is directed to the value of volcanic ash-beds intercalated in other strata as indices to precise correlation of geological terranes. Such ash-beds, when once recognized, are often found to be wide-spread ; and being formed under conditions independent of water-laid basinal deposits pass uninterruptedly from one province to another. At present the most important clue to an horizon of this kind to be looked for in Iowa is an Ordovicic one near the base of the Decorah shales.

Publication Date

1925

Journal Title

Proceedings of the Iowa Academy of Science

Volume

32

Issue

1

First Page

362

Last Page

362

Copyright

©1925 Iowa Academy of Science, Inc.

Language

en

File Format

application/pdf

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