The Green River Formation - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 185

201 amphiumid (congo eel). More common

are turtles ( 201 ) such as Trionyx , a soft-
shelled extant genus, which lives today in
shallow lakes and rivers. Also recorded are
rare pond turtles, snapping turtles, and the
extinct baenid turtles. Lizards are very rare,
but include iguanids, and one species of
snake has been recorded, a neotropical
wood snake ( 202 ; previously misidentified
as a boa constrictor). Crocodiles and
alligators are known commonly from
their preserved scutes and teeth and
from occasional articulated specimens.
Unusually, the alligators outnumber the
crocodiles.

Birds
The Green River Formation has produced
more fossil birds than any other pre-
Pleistocene site in North America
(Grande, 1984). Complete specimens,
disarticulated legs and skulls, feathers, and
even a nest with eggs have all been found
( 203 - 206 ). They include frigate birds

201 The soft-shelled turtle TrionyxTFSK.
Length 1 m 3.3 ft.

202

202 A neotropical wood snake
FBNM. Axial length 98 cm
38 in.

203

203 A wading bird BHIGR.
Length 20 cm 7.8 in beak to
claw.