CAT. No. CR-2-6.

UCB - University of California, Berkeley, USA

Poinar amber collection

1

Holotype: Transitroides morsei Bousfield & Poinar, 1994 [details]

The amber originated from the State of Chiapas in southern Mexico. Amber in that locality is located in a sequence of primarily marine calcareous sandstones and silt with beds of lignite. The amber-bearing strata extend from the Balumtun Sandstone of the lower Miocene to the La Quinta formation of the Upper Oligocene. The deposits have been assigned to the planktonic foraminiferal zones of Globigerina ciperoensis and G. kugleri (Frost and Langenheim, 1974). In the Cenozoic Planktonic Foraminiferal Zonal Sequence, this interval is within zones N3 and N4, assigned to radiometric ages ranging from 22.5 to 26 million years (lower Miocene - upper Oligocene) (Berggren and van Couvering, 1974). Since the amber is secondarily deposited, the above dates provide a minimum age.