Sphinx Mountain, el. is a prominent

mountain peak A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. The topography, topographic terms acme, apex, peak (mountain peak), and zenith are synonymous. The term (mountain top) is generally used ...

on the western face of the

Madison Range The Madison Range is a mountain range located in the Rocky Mountains of Montana and Idaho in the United States. The range was named in honor of future President of the United States, then U.S. Secretary of State James Madison by Meriwether Lewis ...

Madison County, Montana Madison County is a county in the U.S. state of Montana. As of the 2020 census, the population was 8,623. Its county seat is Virginia City. The county was founded in 1865; at the time it was part of the Montana Territory. Geography According ...

. The peak is located in the

Beaverhead National Forest Beaverhead County is the largest county by area in the U.S. state of Montana. As of the 2020 census, the population was 9,371. Its county seat is Dillon. The county was founded in 1865. Much of the perimeter of the county is the Continental D ...

and Taylor Hilgard parcel of the

Lee Metcalf Wilderness The Lee Metcalf Wilderness is located in the northern Rocky Mountains in the U.S. state of Montana. Created by an act of Congress in 1983, this rugged alpine wilderness is divided into four separated parcels typified by complex mountain topograph ...

area. Its prominence and isolation makes it easy to distinguish from

Ennis Ennis ( , meaning 'island' or 'river meadow') is the county town of County Clare, in the mid-west of Ireland. The town lies on the River Fergus, north of where the river widens and enters the Shannon Estuary. Ennis is the largest town in Cou ...

in the

Madison River The Madison River is a headwater tributary of the Missouri River, approximately long, in Wyoming and Montana. Its confluence with the Jefferson and Gallatin rivers near Three Forks, Montana forms the Missouri River. Course The Madison Ri ...

valley. Bear and Indian creeks are tributaries of the Madison River with headwaters on the eastern and northern face of Sphinx Mountain.

Ascents

The first recorded ascent was on July 30, 1913, by Anton W. Asmuth, George Belchic, Stanley H. Wardwell, and someone named Kimball who were students from the Harvard Summer School of Geology. A second recorded ascent was made on August 1, 1919 by R. B. Hevy, John H. Hall Jr., Robert E. Crosby, and Henry J. Hall Jr., also Harvard students. Sphinx Mountain may have been ascended during the 1880s and 1890s by geologists Frank Tweedy, Edward Douglas and or Albert C. Peale during their topographic surveys of the Three Forks quadrangle. The first recorded winter ascent was made in December 1964 by Kit Jones and James W. Clark and has been a popular winter climb ever since.

Geology

USGS Map with Sphinx Conglomerate Annotated

Sphinx Mountain is of interest to geologists as it exposes an unusual formation known as the Sphinx Conglomerate (

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

) which overlays the

Livingston Formation The Livingston Group is a geological formation in Montana whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Dinosaur distributio ...

(

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

). The conglomerate is found only on Sphinx Mountain and the adjacent peak, The Helmet. It was first identified by geologist A. C. Peale during geological surveys of the region in the 1880s.

Notes

{{reflist Mountains of Madison County, Montana Mountains of Montana

Ascents

Geology

See also

Notes