The Stadium Conglomerate is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

San Diego County, California San Diego County (), officially the County of San Diego, is a county in the southwestern corner of the U.S. state of California. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the f ...

. It is found at the northern end of Mission Valley near

San Diego Stadium San Diego Stadium was a multi-purpose stadium on the west coast of the United States, in San Diego, California. The stadium opened in 1967 as San Diego Stadium and was known as Jack Murphy Stadium from 1981 to 1997. From 1997 to 2017, the stadium ...

Geology

The formation consists of a massive cobble

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** C ...

with a dark yellowish-brown coarse-grained sandstone matrix. The conglomerate has dispersed lenses of fossiliferous crossbedded sandstone. It overlies the

Friars Formation The Friars Formation is a geologic formation in San Diego County, Southern California. Geology It is the uppermost unit of the La Jolla Group. The rocks are nonmarine and lagoonal sandstone and claystone, named for exposures along the north ...

, and underlies the sandstone

Mission Valley Formation The Mission Valley Formation is a marine sandstone geologic formation in the Mission Valley region of southwestern San Diego County in Southern California. Geology The formation's sandstone characteristics are: soft and friable, light olive gray ...

Fossil content

It preserves

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

dating back to the

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

epoch of the

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of ...

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

, during the

Cenozoic Era The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...

. The fossils include calcareous

nanoplankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cruc ...

Geology

Fossil content

See also

References

Further reading