PBDB Collection

Alpena (Devonian of the United States)

Where: Michigan (45.1° N, 83.4° W: paleocoordinates 34.4° S, 29.2° W)

• coordinate based on political unit

When: Antrim shale Formation, Middle Devonian (393.3 - 382.7 Ma)

• Remains also found in New Albany and Ohio shales.

Environment/lithology: black shale

• Arnold (1934, p.74): ...the coal layer is almost always of uniform thickness over the extent of the specimen and there is vey little difference in the thickness of the coal regardless of the width. If these were woody axes the coaly material would show as a lens-shaped mass in cross section, the thickness being somewhat proportional to the width. This condition, however, does not exist, and the thicker coal layers are not by any means always associated with broader specimens.

Size class: macrofossils

Preservation: coalified

Collection methods: quarrying, mechanical,

• Arnold (1934, p.75): It is generally assumed that the Antrim shale and other shales of similar age were deposited in a body of water of considerable extent, and the contained vegetable fossils represent material which had been transported for some considerable distance and subjected to prolonged weathering. It seems, then, that these"node-bearing branched" in the black shales may be more correctly interpreted as carbonized strips of cracked bark or wood torn loose from stranded logs beofre fossilization.

Primary reference: C. A. Arnold. 1934. The so-called branch impressions of Callixylon newberryi (Dn) Elkins and Wieland and the conditions of their preservation. Journal of Geology 42(1):71-76 [W. Stein/N. Smith/J. Cassara]more details

PaleoDB collection 14248: authorized by Bill Stein, entered by Nicole Smith on 29.05.2002, edited by Alycia Stigall

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names

Rhynchonellata
Terebratulida - Cranaenidae	Cranaena romingeri Cranaena romingeri Hall 1863

Cordaitales -	Callixylon newberryi Callixylon newberryi First described as "nodes", Arnold believed "nodes" were fissures in the woody material caused by soaking and drying.