Stevens, R. P. (1858). Description of New Carboniferous Fossils from the Appalachian, Illinois and Michigan Coal-fields. The American Journal of Science and Arts, second series. 25(74): 258-265. New Haven.
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Stevens, R. P.
1858
Description of New Carboniferous Fossils from the Appalachian, Illinois and Michigan Coal-fields
The American Journal of Science and Arts, second series