|
Hercosestria040111
''Hercosestria'' is an extinct genus of brachiopods from the Lower and Middle Permian. They were important reef-forming organisms because of their conical shapes, attaching spines, and gregarious habits. It is related to ''Richthofenia''. Species of the genus have been found in Texas (''H. cribrosa'' and ''H. laevis'') and Guatemala (''H. notialis''). References File:HercosestriaSmallCluster040111.jpg, ''Hercosestria cribrosa'' Cooper & Grant 1969 (Roadian, Guadalupian, Middle Permian); Glass Mountains, Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by .... File:HercosestriaPair040111.jpg, ''Hercosestria cribrosa'' Cooper & Grant 1969 (Roadian, Guadalupian, Middle Permian); Glass Mountains, Texas. Permian brachiopods Permian animals of North America Prehistoric brac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roadian
In the geologic timescale, the Roadian is an age or stage of the Permian. It is the earliest or lower of three subdivisions of the Guadalupian Epoch or Series. The Roadian lasted between and million years ago (Ma). It was preceded by the Kungurian and followed by the Wordian. Stratigraphy In 1961, the regional timescale used for the southeastern US had the Wordian and Capitanian as subdivisions of the Guadalupian. Efforts to correlate the Permian stratigraphy of the southeastern US with that of Russia led to the conclusion that between the Wordian stage and the Russian Artinskian stage, another stage needed to be introduced. This stage, the Roadian Stage, was established in 1968 and took its name from the Road Canyon Formation in Brewster County, Texas, formerly considered the lower (oldest) part of the Word Formation. The stage was added to the internationally used IUGS timescale in 2001.; 1999: ''Proposal of Guadalupian and Component Roadian, Wordian and Capitanian St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
