The Green River Formation - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 178

Wyoming) did not develop until
the early Eocene, and only the former
lasted into middle Eocene times.
The early Eocene was, therefore, the only
time when the three lakes existed
contemporaneously, and both the base
and top of the Green River Formation are
therefore diachronous.

Fossil Lake was the smallest of the
three lakes and persisted for the shortest
time (early Eocene only), but is the best
known and has produced the majority
of the fossil fish sold commercially
throughout the world. Its sediments
are grouped into two members ( 189 ),
the Fossil Butte Member, some 60-80 m

189

Yellow areas represent Green River Formation sediments

Eocene
Fossil Lake

Eocene
Lake Gosiute

Eocene phase
of Lake Uinta

Uinta Basin
and
Central Utah

Million
Years
B.P.

Provincial
Age

Fossil
Basin

Bridger
Basin

Washakie
Basin

Epoch

37.0

Uinta
Formation

?

47.5

Green
River
Formation

Laney Shale Member

??

Bridger Fm
Angelo Mbr

49.6

Wilkins Peak
Member

Fontanelle
Tipton Shale
Member

?

Luman

?

?

?

?

Wasatch
Formation

Wasatch Formation

Flagstaff Mbr

55.0

189 Diagram to show the stratigraphy of the Green River Formation in Fossil Lake, Lake
Gosiute and Lake Uinta after Grande, 1984.