Yellowstone Paleo Survey: Localities

Localities

Fossil localities have been known in Yellowstone prior to the Hayden surveys. The long ridge separating Lamar Valley and Mirror Plateau has been referred to as Specimen Ridge since before 1870. The name was probably established by prospectors who were aware that the area contained an abundance of amethysts and silicified wood (Whittlesley 1988).

As part of the 1996_97 Yellowstone Paleontological Survey, the park was divided into paleontological resource regions that reflect areas of geologic or stratigraphic affinities. The boundaries of these regions do not correspond to the administrative boundaries established by the park. Fossil localities within each paleontological region are identified in quotation marks.


Petrified stumps in Lamar Valley.

Gallatin Region

The Gallatin Region is an extremely large mountainous area in the northwest part of the park that includes some of the best exposures of Paleozoic and Mesozoic sedimentary rocks. Mount Holmes is the southernmost point of this region. Potentially fossiliferous outcrops occur throughout this mountain range extending to the northern and western boundaries of the park.

Paleozoic sediments are widespread throughout the Gallatin Range, including units in Wolsey Shale, Meagher Limestone, Pilgrim Limestone, Snowy Range Formation, Bighorn Dolomite, Jefferson Formation, and Madison Group. Mesozoic units include Ellis Group, Morrison Formation, Mowry Shale, Frontier Shale and other unidentified Cretaceous units. The Sepulcher Formation is the only known fossil-bearing unit from the Tertiary epoch of this region.

Recommended Mapping Projects

• Establish a database for all known fossil localities within the park.

• Establish a standardized system for cataloging and identifying park fossil localities with cross-references for any previously used numbers or site names.

• Map all fossil localities with GPS and incorporate the data into Yellowstone's GIS System.

• Use digital mapping system to generate a paleontological locality map for the park.

"Specimen Creek": The first known map of the Gallatin Petrified Forest is found in a 1935 report, "Petrified Sequoia Trees in the Northwest Corner of Yellowstone National Park" by Dr. Paul A. Young of Bozeman. He identified and mapped 21 standing trees in the Gallatin/Specimen Creek area and noted the discovery of leaf impressions of poplar, willow, and magnolia trees. Most of the previous paleobotanical fieldwork had been conducted in the Lamar River Valley.

Andrews (1939) surveyed the Gallatin region of the park in the 1930s, collecting specimens in the Gallatin Petrified Forest in 1936. He reported at least 12 successive layers of fossil forest around Bighorn Peak, predominantly consisting of Sequoia magnifica, and fossil impressions of S. langsdorfi along Bighorn Creek. The petrified trees are preserved in the Eocene Sepulcher Formation.

"Crowfoot Ridge": The Crowfoot Ridge section provides the most complete and best exposed section of Cambrian rocks between the Flathead Sandstone and the Pilgrim Limestone in the park and contains more Upper Cambrian fossils than any other section in Montana. The fossil brachiopods from the Flathead Sandstone in this area are the only known fossils from this unit in Montana.

"Three Rivers Peak": Excellent exposures of the Snowy Range Formation and the Pilgrim Limestone occur on Three Rivers Peak at the head of the Gallatin River. Algae, brachiopods, and trilobites are known from the Snowy Range Formation and fossil fragments from the Pilgram Limestone.

"Mount Holmes" (Trilobite Point): Mt. Holmes contains good exposures of Cambrian units, including Wolsey Shale, Meagher Limestone, Pilgrim Limestone and Snowy Range Formation. These units also occur on adjacent Dome Mountain and Three Rivers Peak. In 1878, William Henry Holmes named a 10,003 foot high point in the Gallatin Range of Yellowstone "Trilobite Point." A sedimentary exposure on the lower eastern summit of Mt. Holmes contains trilobite fossils.

The Gallatin Region has many other localities, including "Fawn Pass" and "Fan Creek," that occur near exposures of Jurassic strata and are often mentioned in regard to the presence of fossils.

Mount Everts Region

This region is dominated by Mount Everts, where a thick sequence of Cretaceous marine and non-marine rocks are well exposed. The north entrance road in Gardner Canyon marks the western extent of this region. Its western and northern faces have outcrops of Landslide Creek Formation, Everts Formation, Eagle Sandstone, Telegraph Creek Formation, Cody Shale and Frontier Sandstone; on its eastern slope are small outcrops of Madison Group (Mississippian), Ellis Group and possible Morrison Formation (Jurassic) rocks.

Although the stratigraphy of Mount Everts is not well established, preliminary surveys suggest the potential for significant paleontological discoveries. Numerous fossil plant and vertebrate localities have been recently identified on Mount Everts. During 1997, Bianca Cortez discovered two new fossil leaf localities that have yielded fern, willow and other broadleaf fossils. The remains of an unidentified plesiosaur, a turtle carapace, and a dinosaur eggshell fragment have also been recovered from Mount Everts (Jack Horner, pers. commun., 1995). A systematic collection of fossils from this area would assist efforts in interpreting the Late Cretaceous geology of Yellowstone.

Tower Region

This region, which includes Tower Falls, Tower Junction, Elk Creek, Crescent Hill and the northeast face of Prospect Peak, contains petrified trees, large exposures of Sepulcher Formation and small outcrops of Lamar River Formation.

"Petrified Tree": This fossil is located 1.5 miles east of Tower Junction, just east of Yancey Creek at the end of a small spur road off the Grand Loop Road. After souvenir hunters destroyed one petrified tree in the area, the remaining one was enclosed by an iron fence in 1907.

"Yancey's Forest": A group of fossil stumps below Lost Lake, approximately 1.5 miles by road from Tower Falls Ranger Station.

"Roosevelt Lodge": Pieces of petrified wood are incorporated into the foundation of the Roosevelt Lodge.

Lamar Region

The Lamar Region is limited to the ridge on the south side of the Lamar River, and includes well-exposed Lamar River Formation and Langford Formation. Small exposures of Sepulcher Formation occur at the northwest end of "Specimen Ridge." Its fossiliferous exposures extend from the northwest edge of "Specimen Ridge" to Timothy Creek just south of Mirror Plateau and include "Amethyst Mountain," "Fossil Forest," and "Mirror Plateau."

"Amethyst Mountain/Specimen Ridge": This locality is 10 miles long, lies 2,000 feet above the valley, and exposes 27 successive layers of fossil forest.

"Fossil Forest": The paleontological significance of the region comes from the presence of standing fossil tree trunks and a stratigraphic succession of at least two dozen fossil forests that were first recognized by Knowlton (1914). "Fossil Forest" has been extensively studied by Dorf and other paleobotanists.

Northeast Region

The Northeast Region extends from Buffalo Plateau to the extreme northeast corner of the park, including the area north of the Lamar River and north of Soda Butte Creek. The Buffalo Plateau, especially the east edge near Slough Creek, contains fossiliferous units, with middle Cambrian rocks overlain by the Snowy Range Formation. Ordovician and Devonian units occur above the Snowy Range Formation and the section is capped by the Eocene Langford Formation.

The ridge between Slough Creek and Pebble Creek, including Bison Peak and Mount Hornaday, is covered by large exposures of Lamar River Formation and Wiggins Formation. Standing fossil trunks and petrified wood is reported from the area around Bison Peak.

Barronette Peak and Meridian Peak have exposures of Cambrian Snowy Range Formation and the Mississippian Madison Group and are capped by Lamar River Formation. Barronette Peak has standing petrified tree trunks.

The Pebble Creek campground provides fossiliferous exposures of the Madison Group. This unit is easily accessible and should be monitored for impacts from park visitors.

"Lamar Cave": A sequence of late Holocene faunal remains, including 36 mammal species, was collected from 10 stratigraphic units in this cave, which is located in the northern part of the park.

Upper Lamar Region

The Upper Lamar Region includes the area east of the Lamar River and south of Soda Butte Creek and extends to the east boundary. The Eocene Wiggins Formation is extensively exposed near the east boundary, including Hoodoo Basin, Saddle Mountain, Upper Lamar River, Calfee Creek, Mount Norris, and Amphitheater Mountain. Important fossil vertebrate assem
blages have been found in this unit just east of the park. This area should be considered a high priority for future paleontological surveys.

The Lamar River Formation is widely exposed along Miller Creek, Cache Creek, and on Cache Mountain, where petrified wood and stumps are reported. At least six levels of standing stumps could be identified at the petrified forest located about four miles above the mouth of Miller Creek, on the north side, at an elevation of about 7,300 feet.

Limited exposures of the Mississipian Madison Group occur just northeast of Soda Butte and on the west slope of Abiathar Peak. The Cambrian Snowy Range Formation is present on the north slope of Abiathar Peak.

"Cache Creek": Petrified wood deposits covering several acres are located about seven miles above the mouth of Cache Creek, on the south bank. The wood is scattered on a slope that extends for 800 feet, with most of the trunks standing upright only two to three feet above the surface. The largest stump is six-feet tall and four feet in diameter.

"The Thunderer": This locality bears numerous fossil trunks, most standing upright about two feet above the surface.

Eastern Boundary Region

The Middle Eocene Langford Formation, which is widely exposed in the area between the park's eastern boundary and Yellowstone Lake, includes volcaniclastic rocks (approximately 46 million years B.P.) that contain paleobotanical specimens. Five sites identified at the "Lake Butte" locality have yielded both fossil leaf impressions and petrified wood. All of the leaf material was identified as sycamore of the genus Macginitiea.

Accumulations of transported petrified wood can be found along the banks of the streams and rivers on the eastern boundary Paleontological surveys for the sources of this material, both within and outside the park, have not yet been done.

Southeast Region

Large exposures of the Eocene Wiggins Formation occur in the southeast corner of the park on Two Ocean Plateau and near the Trident. According to Aubrey Haines, a ranger named Harry Trischman indicated that he found "sea shells" on the Trident during the 1930s. Although fossils have not been documented from this area, they are known from adjacent areas just outside of the park.

Snake River Region

Large exposures of Paleozoic and Mesozoic sedimentary rocks occur in the Snake River area. Two exposures of potentially fossiliferous rocks occur along the park's southern boundary. One of them forms a triangle between the south slope of Mount Sheridan, the Harebell Patrol Cabin, and along the south boundary to just east of the South Entrance. This area contains exposures of Madison Limestone (Mississippian), Phosphoria Formation (Permian), possible Morrison Formation (Jurassic), Mowry Shale (Lower Cretaceous), and Frontier Formation, Cody Shale and Harebell Formation (Upper Cretaceous).

The other more eastern and slightly larger triangular exposure extends between Channel Mountain on the north, to just west of Fox Creek Patrol Cabin, and along the south boundary to the Harebell Patrol Cabin. This section contains exposures of the Morrison Formation (Jurassic), Mowry Shale (Lower Cretaceous), and Frontier Formation, Cody Shale and Harebell Formation (Upper Cretaceous).

Birch Hills Region

Birch Hills, which has limited outcrops of Gallatin Limestone (Cambrian), Madison Limestone (Mississippian), and Phosphoria Formation (Permian). is the only region in the southwest part of the park that has the potential for fossiliferous exposures. The area has not been surveyed for paleontological resources and no specimens have been reported from this area. A systematic survey is recommended.

Interpretation