Fossiliferous Amber from the Eocene (Claiborne) of the Gulf Coastal Plain

Middle Eocene lignite and lignitk shale in the central Arkansas Coastal Plain contain fossiliferous amber in association with commercially exploited refractory clay. A rich, excellently preserved spore and pollen assemblage occurs with the amber and establishes the age of the strata as lower Claiborne (lower middle Eocene). Similarity of infrared absorption spectra of the Claiborne amber to infrared spectra of Holocene Shorea sp. resin suggests the tropical, resinous hardwood family Dipterocarpaceae as a possible botanical source. Preliminary examination of approximately 300 insect inclusions sufficiently well prepared for examination indicates that the insect orders Hemiptera (Homoptera), Diptera, and Hymenoptera dominate the fauna. Five additional insect orders are sparsely represented; there are also rare Araneae and plant remains. The Claiborne amber fauna seems characterized by relatively small individual size and low taxonomic diversity, with many individuals but relatively few species.