The Green River Formation - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 193

primitive holostean types, Atractosteus , the
garfish, and Cyclurus , the bowfin, which
are not so common at Green River. Also a
single specimen of an eel is known from
Messel.
Messel plants are dominated by
angiosperms and many, such as palms,
citrus, laurels, tea, grape, and walnut
indicate a subtropical climate as at Green
River. Gymnosperms are scarce,
suggesting they did not live close to the

lake, but water lilies testify to open,
oxygenated water conditions.
The Messel Lake was in existence for
about 100,000 years, and it is thought that
the fossil-bearing regions represent
deeper, anoxic depressions within this
large persistent basin, most of which was
well oxygenated. This model explains the
exquisite preservation, often of soft tissue,
for which Messel is famed, and which is
rarely seen at Green River.

F URTHER R EADING
Baer, J. L. 1969. Paleoecology of cyclic
sediments of the lower Green River
Formation, central Utah. Brigham
Young University Geological Studies
16 , part 1.
Cope, E. D. 1884. The Vertebrata of the
Tertiary formations of the West.
United States Geological and
Geographical Survey of the
Territories 3 , 1-1009.
Fouche, T. D. 1976. Revision of the lower
part of the Tertiary system in the
central and western Uinta Basin,
Utah. United States Geological
Survey Bulletin 1405-C , 1-7.
Grande, L. 1984. Paleontology of the
Green River Formation, with a review
of the fish fauna (2nd edn.).
Geological Survey of Wyoming
Bulletin 63 .
Grande, L. 1994. Studies of
paleoenvironments and historical
biogeography in the Fossil Butte and
Laney members of the Green River
Formation. Contributions to Geology,
University of Wyoming 30 , 15-32.

Grande, L. 2001. An updated review of
the fish faunas from the Green River
Formation, the world's most
productive freshwater Lagerstätten.
1-38. In: Eocene Biodiversity:
Unusual Occurrences and Rarely
Sampled Habitats . G. F. Gunnell
(ed.). Kluwer Academic/Plenum
Publishers, New York.
Grande, L. and Buchheim, H. P. 1994.
Paleontological and sedimentological
variation in early Eocene Fossil Lake.
Contributions to Geology, University
of Wyoming 30 , 33-56.
Hayden, F. V. 1871. Preliminary report of
the US Geological Survey of
Wyoming and portions of contiguous
territories. United States Geological
and Geographical Survey of the
Territories 4 th Annual Report , 1-511.
Selden, P. and Nudds, J. 2004. Evolution
of Fossil Ecosystems . Manson,
London.
Surdam, R. C. and Wolfbauer, C. A. 1975.
Green River Formation, Wyoming:
playa-lake complex. Geological
Society of America Bulletin 86 ,
335-345.