Point Lookout Sandstone
Encyclopedia
The Point Lookout Sandstone is a Cretaceous
bedrock
formation occurring in New Mexico
and Colorado
.
, Colorado
, in the Paradox Basin
, and later described by Allen and Balk in 1954 as part of the Mesaverde Group in the San Juan Basin
in New Mexico
.
The formation was described by Cather (2010) as "Light gray to buff medium to finegrained, cross-bedded
sandstone."
remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus
.
The ammonite
Clioscaphites vermiformis was identified in the formation.
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...
formation occurring in New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
and Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
.
Description
The sandstone was first described by A. J. Collier for exposures in cliffs at Point Lookout, Montezuma CountyMontezuma County, Colorado
Montezuma County is the southwesternmost of the 64 counties of the state of Colorado of the United States. The county population was 23,830 at U.S. Census 2000...
, Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, in the Paradox Basin
Paradox Basin
The Paradox Basin is an asymmetric foreland basin located mostly in southeast Utah and southwest Colorado, but extending into northeast Arizona and northwest New Mexico. The basin is a large elongate northwest to southeast oriented depression formed during the late Paleozoic Era...
, and later described by Allen and Balk in 1954 as part of the Mesaverde Group in the San Juan Basin
San Juan Basin
The San Juan Basin is a geologic structural basin in the Four Corners region of the Southwestern United States; its main portion covers around , encompassing much of northwestern New Mexico, southwest Colorado, and parts of Arizona and Utah....
in New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
.
The formation was described by Cather (2010) as "Light gray to buff medium to finegrained, cross-bedded
Cross-bedding
In geology, the sedimentary structures known as cross-bedding refer to horizontal units that are internally composed of inclined layers. This is a case in geology in which the original depositional layering is tilted, and the tilting is not a result of post-depositional deformation...
sandstone."
Fossils
DinosaurDinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
The ammonite
Ammonite
Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...
Clioscaphites vermiformis was identified in the formation.