Age and History of Investigation
This formation has been dated to the early to middle Callovian stage of the latest Middle Jurassic. The type locality and place for which the unit is named is Entrada Point, located in the northern part the San Rafael Swell in Emery County, Utah.
Entrada Sandstone was named as one of the four formations of the San Rafael Group by Gilluly and Reeside in 1928. Gregory and Moore worked out the geographic extent of the formation and gave an overview of it in 1931. The extent was revised several times afterwards (most recently in 1992 by Condon). It was divided into Gunsight Butte, Cannonville, and Escalante members by Thompson and Stokes in 1970. The principal reference for the formation was written in 1988 by Peterson.
Read more about this topic: Entrada Sandstone
Famous quotes containing the words age and, age and/or history:
“It is as if, to every period of history, there corresponded a privileged age and a particular division of human life: “youth” is the privileged age of the seventeenth century, childhood of the nineteenth, adolescence of the twentieth.”
—Philippe Ariés (20th century)
“If youth but knew; if age but could.
Wives in their husbands’ absences grow subtler,
And daughters sometimes run off with the butler.”
—George Gordon Noel Byron (1788–1824)
“The whole history of civilisation is strewn with creeds and institutions which were invaluable at first, and deadly afterwards.”
—Walter Bagehot (1826–1877)