Frontier Formation

{{Short description|Geological formation in the United States}}

{{Infobox rockunit

| name = Frontier Formation

| image = Frontier Sandstone (Upper Cretaceous; western Dinosaur National Monument, Utah, USA) 14 (48822462432).jpg

| caption = Frontier Formation in Utah (Dinosaur National Monument)

| type = Geological formation

| age = Cenomanian-Coniacian

| period = Cenomanian-Coniacian

| prilithology = Sandstone

| otherlithology = Shale

| namedfor =

| namedby = W. C. Knight, 1902W.C. Knight, 1902, Eng. and Min. Jour., v. 73, p. 721

| region = North America

| country = United States

| coordinates =

| unitof =

| subunits = Torchlight Sandstone Member, Peay Sandstone Member

| underlies = Cody Shale

| overlies = Mowry Shale, Thermopolis Shale

| thickness =

| extent = see text

| area =

| map =

| map_caption =

}}

File:Frontier Fm.jpg

The Frontier Formation is a sedimentary geological formation whose strata date back to the Late Cretaceous. The formation's extents are: northwest Colorado, southeast Idaho, southern Montana, northern Utah, and western Wyoming. It occurs in many sedimentary basins and uplifted areas.

The formation is described by W.G. Pierce as thick, lenticular, grey sandstone, gray shale, carbonaceous shale, and bentonite.Pierce, W.G., 1997, Geologic map of the Cody 1 degree x 2 degrees quadrangle, northwestern Wyoming: U.S. Geological Survey, Miscellaneous Geologic Investigations Map I-2500, scale 1:250000.

Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. {{ISBN|0-520-24209-2}}.