Skull Spring
Basic information
Sample name: Skull Spring
Reference: C. L. Gazin. 1932. A Miocene mammal fauna from south-eastern Oregon. Carnegie Institution of Washington Publication 418:37-86 [ER 4177]
Geography
Country: United States
State: Oregon
County: Malheur
Coordinate: 45° 30' N, 117° 47' W
Coordinate basis: estimated from map
Scale: outcrop
Formation: Butte Creek Volcanic Sandstone
Time interval: Middle Miocene
Ma: 15.4
Age basis: K-Ar
Geography comments: "twenty-eight miles south of Harper... and approximately three miles northwest of Skull Spring... The local drainage is part of a tributary known as Dry Creek or Beaver Creek"
shown on the map of Shotwell (1968, Fig. 8) as about 5 km due south of the Red Basin localities, and implied to be in the same unit
coordinate based on this map
implied to be from the "Payette formation" based on superposition of the beds over the "Owyhee basalt", but apparently from the Butte Creek Volcanic Sandstone based on Shotwell (1968)
Evernden et al. (1964) provide a K-Ar date on sanidine of 15.0 Ma for the "Payette Fm., Skull Spring Fauna" (meaning the Butte Creek Volcanic Sandstone) and Evernden and James (1964) a date of 15.1 Ma for a "Red Ridge Basin" sample collected by Shotwell
based on the critical table of Dalrymple (1992), the 15.0 Ma date should be recalibrated as 15.40 Ma and the 15.1 Ma date as 15.50 Ma
shown on the map of Shotwell (1968, Fig. 8) as about 5 km due south of the Red Basin localities, and implied to be in the same unit
coordinate based on this map
implied to be from the "Payette formation" based on superposition of the beds over the "Owyhee basalt", but apparently from the Butte Creek Volcanic Sandstone based on Shotwell (1968)
Evernden et al. (1964) provide a K-Ar date on sanidine of 15.0 Ma for the "Payette Fm., Skull Spring Fauna" (meaning the Butte Creek Volcanic Sandstone) and Evernden and James (1964) a date of 15.1 Ma for a "Red Ridge Basin" sample collected by Shotwell
based on the critical table of Dalrymple (1992), the 15.0 Ma date should be recalibrated as 15.40 Ma and the 15.1 Ma date as 15.50 Ma
Environment
Lithology: ash
Habitat comments: "The beds... consist principally of ash and lie on the irregular surface of the rhyolite... No complete skeletons were found. Most of the scattered remains were preserved in nodules"
Methods
Life forms: carnivores,rodents,ungulates
Sample size: 125 specimens
Museum: California Institute of Technology
Sampling comments: "Attention was first directed to the so-called Skull Spring occurrence by Mr. C. J. Bush of Harper, Oregon"
collected "during the summer field seasons of 1928 and 1929" by the California Institute of Technology
"Many of the specimens were collected in small dry stream beds along the bases of the more pronounced ridges" mostly as float, but "other specimens were located in place"
collected "during the summer field seasons of 1928 and 1929" by the California Institute of Technology
"Many of the specimens were collected in small dry stream beds along the bases of the more pronounced ridges" mostly as float, but "other specimens were located in place"
Metadata
Sample number: 4639
Contributor: John Alroy
Enterer: John Alroy
Modifier no: John Alroy
Created: 2025-01-04 21:54:19
Modified: 2025-01-06 02:26:38
Abundance distribution
23 species
7 singletons
total count 125
geometric series index: 46.4
Fisher's α: 8.276
geometric series k: 0.8447
Hurlbert's PIE: 0.8465
Shannon's H: 2.4224
Good's u: 0.9445
Each square represents a species. Square sizes are proportional to counts.
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Register
| †Paratomarctus temerarius | 1 | |
| Wang et al. (1999): "Tomarctus cf. brevirostris" (assigned to Tomarctus rurestris by Downs (1956) and Shotwell (1968) | ||
| †Euoplocyon brachygnathus | 1 | |
| Wang et al. (1999): "Euoplocyon ? sp." | ||
| Canidae indet. | 1 | |
| ? | ||
| Amphicyon sinapius = †Cynelos sinapius | 2 | |
| †Amphicyon cf. frendens | 2 | |
| †Pliocyon cf. medius | 1 | |
| †Ursavus cf. primaevus | 1 | |
| Hunt (1998): "Hemicyon ? n. sp." | ||
| †Martes (Tomictis) gazini | 1 | |
| Hall (1981): type; "Mustelid n. sp." | ||
| Sciurus malheurensis = †Protospermophilus malheurensis | 2 | |
| type | ||
| Sciurus tephrus = †Spermophilus tephrus | 3 | |
| type: includes type of "Citellus ridgwayi" | ||
| †Liodontia alexandrae | 14 | |
| 11 enumerated specimens and "a number of isolated teeth" | ||
| †Hesperogaulus gazini | 41 | |
| Korth (1999): type; "Mylagaulus cf. laevis"; approximate count | ||
| Diprionomys ? oregonensis = †Balantiomys ? oregonensis | 4 | |
| type | ||
| Hypohippus sp. | 4 | |
| may include Gazin''s "Chalicothere ? sp." according to Skinner (1968) | ||
| †Parahippus aff. coloradensis | 3 | |
| near this species | ||
| Merychippus isonesus = †Acritohippus isonesus | 17 | |
| a maxilla, a mandible, and an astragaus articulated with a calcaneum, plus 14 upper cheek teeth of "Merychippus seversus" studied by Downs (1961) and almost certainly isolated lowers | ||
| †Merychippus relictus | 3 | |
| Bode (1934); Merychippus brevidontus is also present according to Bode and Shotwell (1968), but no specimens are listed | ||
| Rhinocerotidae indet. | 7 | |
| "tarsal and carpal elements, ungual phalanges, the distal end of a tibia and fragments of teeth" | ||
| Tayassuinae indet. | 1 | |
| "Platygonus ? sp.": Thinohyus or Desmathyus according to Gazin (1938) | ||
| Ticholeptus sp. | 3 | |
| ?: ID confirmed by Shotwell (1968); count may be a minimum | ||
| †Dromomeryx aff. borealis | 8 | |
| near this species); count may be a minimum | ||
| Rakomeryx cf. americanus = †Bouromeryx cf. americanus | 2 | |
| Shotwell (1968): "Blastomeryx ? sp." | ||
| Paracosoryx sp. | 3 | |
| Frick (1937): his "Cosoryx (Paracosoryx)"; Gazin''s "Merycodus ? sp. a" and "Merycodus ? sp. b" | ||