Middle Park (Middle) (Miocene of the United States)

Where: Grand County, Colorado (40.2° N, 106.1° W: paleocoordinates 41.1° N, 101.9° W)

• coordinate based on political unit

When: Troublesome Formation, Early/Lower Miocene (23.0 - 16.0 Ma)

• lower part of "orange-gray siltstone and sandstone unit"

•ash bed at "presumably" the same level dated at 20.0 +/- 2.3 Ma FT on sphene and 18.0 +/- 2.0 Ma FT on zircon: Izett 1975

• group of beds-level stratigraphic resolution

Environment/lithology: terrestrial; gray sandstone

Size class: macrofossils

Primary reference: G. E. Lewis. 1969. United States Geological Survey Professional Paper 650-B [J. Alroy/J. Alroy]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 18978: authorized by John Alroy, entered by John Alroy on 27.09.1993

Creative Commons license: CC BY (attribution)

Taxonomic list

• I presume that Barger Gulch, Blue Face Jaw, and Slump (= Fence) are at this level because Rich 1981 implies they are at the same level as a "lower" Troublesome Fm. fauna that is identical to Izett's; these three localities are all from near Kremmling in Grand Co.
Mammalia
 Artiodactyla - Merycoidodontidae
Merycochoerus matthewi Loomis 1924 oreodont
Merycochoerus magnus3 Loomis 1924 oreodont
 Theriamorpha - Erinaceidae
Parvericius montanus2 Koerner 1940 hedgehog
Blue Jaw Face
Stenoechinus tantalus2 Rich and Rasmussen 1973 hedgehog
Slump
Brachyerix macrotis2 Matthew 1933 hedgehog
Barger Gulch West
 Rodentia - Heteromyidae
Dikkomys sp.1 Wood 1936 rodent
Blue Jaw Face, Barger Gulch
 Rodentia - Mylagaulidae
Mesogaulus cf. paniensis Matthew 1902 rodent