USGS 5425 - College Hill: Priabonian, Oregon

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Scaphopoda - Dentaliida - Dentaliidae
Dentalium (? Fissidentalium) laneensis Hickman 1969
Bivalvia - Cardiida - Mactridae
Spisula eugenensis (Clark 1925)
recombined as Mactromeris eugenensis
Cephalopoda - Nautilida - Aturiidae
Aturia angustata (Conrad 1849)
original and current combination Nautilus angustatus
Gastropoda - Naticidae
Polinices washingtonensis (Weaver 1916)
Neverita thomsonae Hickman 1969
synonym of Glossaulax reclusiana
Gastropoda - Ficidae
Ficus modesta (Conrad 1848)
Gastropoda - Neogastropoda - Perissityidae
Nekewis cf. nehalemensis (Anderson and Martin 1914)
Hickman 1976
Gastropoda - Neotaenioglossa - Calyptraeidae
Crepidula ungana Dall 1908
see common names

Geography
Country:United States State/province:Oregon County:Lane
Coordinates: 44.0° North, 123.1° West (view map)
Paleocoordinates:44.4° North, 110.8° West
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period:Paleogene Epoch:Eocene
Stage:Priabonian 10 m.y. bin:Cenozoic 3
Key time interval:Priabonian
Age range of interval:37.71000 - 33.90000 m.y. ago
Stratigraphy
Formation:Eugene
Stratigraphic resolution:bed
Stratigraphy comments: Eugene Formation can be subdivided faunally: a lower unit correlating to the Keasey Fm, a middle unit correlating to the Gries Ranch Beds of WA, and a upper unit correlated with the Pittsburg Bluff Fm. Thickness of formation may be up to 15,000 feet, but probably around 5,000 feet. Most of the outcrops are scattered so it is difficult to estimate their relative stratigraphic placement
Lithology and environment
Primary lithology:tuffaceous,brown,gray,blue lithified sandstone
Secondary lithology:tuffaceous,brown,gray,blue siltstone
Includes fossils?Y
Includes fossils?Y
Lithology description: Tuffaceous and highly feldspathic sandstone or siltstone which is bluish-gray to olive when fresh and weathers to a buff or orange-brown color. Gray sandstone and siltstone beds may range from several to 50 feet in thickness and are interbedded with minor amounts of sandy sahel and clay shale, occasional beds of conglomerate, and thin lenses of gray or buff-colored volcanic ash
Environment:transition zone/lower shoreface
Geology comments: Retallack et al. (2000): Near-shore, shallow-marine environments are indicated by sedimentary structures such as hummocky cross-bedding, shallow water trace fossils such as Planolites and Thalassinoides and common glauconite and phosphate nodules (Mears, 1989).
Hickman (1969): Several lines of evidence suggest that most of the Eugene Formation was deposited in shallow water, at depths no greater than 30 fathoms. The coarse, tuffaceous, and arkosic character of many beds and the interfingering of the Eugene Formation with non-marine tuffaceous rocks to the east and south indicates the proximity of the Oligocene shoreline. Although mollusks are generally not good indicators of depth, genera such as Panopea, Modiolus, Solen, and Spisula are presently restricted to depths of less than 40 fathoms. The high diversity of the benthonic fauna is an indication that the environment was not one of a bay or otherwise highly restricted environment. The absence of planktonic forms is typical of turbid, near-short environments. In the same units with these relatively undisturbed infauna! assemblages there are occasional thin layers of concentrated shell material which show definite signs of reworking and current sorting. The layers range from 1 to 10 cm in thickness and cannot be traced over great distances. The shells in these layers are small and include an admixture of infaunal and epifaunal species. The shells show little sign of wear or breakage, but many of the pelecypod valves are disarticulated, indicating some degree of transport. The scaphopods in these layers show parallel alignment by the current. There is also evidence that currents were intermittent and fluctuating in strength: the assemblages contain varying percentages of large shells mixed in with the smaller ones, and in some places there are higher proportions of broken and abraded shell debris mixed in.
Taphonomy
Modes of preservation:body,mold/impression,trace
Size of fossils:macrofossils
Collection methods and comments
Collection excludes:some macrofossils
Collection methods:selective quarrying,field collection,survey of museum collection
Reason for describing collection:taxonomic analysis
Museum repositories:CAS
Collection method comments: Collections held at University of Oregon, University of California, Californian Academy of Sciences (CAS), United States Geological Survey (USGS), and Stanford University (NP).
Taxonomic list comments:Exhaustive for mollusca
Metadata
Also known as:USGS 5425a-d, 17015, 17041, 17942; UO 12, 29, 127, 164, 128, 129; UC 4080-4084; #4 (Hickman)
Database number:38936
Authorizer:A. Hendy, M. Uhen Enterer:A. Hendy, M. Uhen
Modifier:M. Clapham Research group:marine invertebrate
Created:2004-05-17 11:40:22 Last modified:2019-08-08 21:44:09
Access level:the public Released:2004-05-17 11:40:22
Creative Commons license:CC BY
Reference information

Primary reference:
10532. C. J. S. Hickman. 1969. The Oligocene marine molluscan fauna of the Eugene Formation in Oregon. University of Oregon Museum of Natural History Bulletin 16:1-112 [A. Miller/A. Hendy/P. Wagner]

Secondary references:

10878 C. J. Hickman. 1976. Bathyal gastropods of the family Turridae in the Early Oligocene Keasey Formation in Oregon, with a review of some deep-water genera in the Paleocene of the Eastern Pacific. Bulletins of American Paleontology 70(292):1-119 [A. Miller/A. Hendy/P. Wagner]