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Authors

Samuel Calvin

Document Type

Research

Abstract

Since Professor Macbride's paper on Bennettites dacotensis was published in the American Geologist for October, 1803, there have been numerous inquiries respecting the exact geological horizon from which the cycads were derived. The close resemblance and the intimate relationship indicated between the Dakota fossil and Tysonia marylandica Fontaine, while not conclusive, would point toward a common horizon for the two species, and so make it possible to correlate the Potomac formation with a definite Mesozoic horizon in the northwest. Professor Macbride's paper left the stratigraphical position of his species undecided. To settle, if possible, the question definitely the writer recently made a visit to the locality that furnished the types of Macbride's species.

Publication Date

1893

Journal Title

Proceedings of the Iowa Academy of Sciences

Volume

1

Issue

Pt. 4

First Page

18

Last Page

22

Copyright

©1893 Iowa Academy of Science, Inc.

Language

en

File Format

application/pdf

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