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Ordovician rocks in Illinois are divided into three series, each separated by an unconformity; from oldest to youngest, these are the Canadian, Champlainian, and Cincinnatian series. Ordovician features in Illinois include the now-buried Glasford Structure in Peoria County , a crater caused by a meteorite impact roughly 455 million years ago.
A gap in the local rock record spans the entire Permian period, so there are no rocks of this age in Illinois in which fossils could have been preserved. [2] However, one notable local event following the Pennsylvanian was the meteor impact that occurred near modern Des Plaines. [13]
The Illinois Basin is a Paleozoic depositional and structural basin in the United States, centered in and underlying most of the state of Illinois, and extending into southwestern Indiana and western Kentucky. The basin is elongate, extending approximately 400 miles (640 km) northwest-southeast, and 200 miles (320 km) southwest-northeast.
The first settlers came to Thornton, Illinois, in 1834. Gurdon Saltonstall Hubbard received 160 acres of land from Watseka, his Potawatomi wife. In 1836 Hubbard opened the first quarry on Kinzie Street. The site was abandoned because the stone was too deep and of poor quality. Fred Gardner opened a quarry in 1846, and Stephen Crary opened one ...
The type locality is the Mazon River (or Mazon Creek), a tributary of the Illinois River near Morris, Grundy County, Illinois. The 25 to 30 meters of shale were formed approximately , during the Pennsylvanian period. The fossiliferous concretions are usually found within the thickest deposits of the Francis Creek Shale.
The oldest dated rocks formed on Earth, as an aggregate of minerals that have not been subsequently broken down by erosion or melted, are more than 4 billion years old, formed during the Hadean Eon of Earth's geological history, and mark the start of the Archean Eon, which is defined to start with the formation of the oldest intact rocks on Earth.
[3] Landmark name Image Location County Culture Comments; 1: Albany Mounds Site: Albany: Albany Mounds Trail 4]: Whiteside: Middle Woodland: Hopewell: 2: Alton Military Prison Site: Alton: inside the block bounded by Broadway and William, 4th, and Mill Sts. 5]: Madison: Euro-American: 3: Apple River Fort Site: Elizabeth: 0.25 miles east-southeast of the junction of Myrtle and Illinois Sts. 6 ...
The Modoc Rock Shelter site was discovered in 1951 by amateur archaeologist Irvin Peithmann, who is known for teaching himself about the customs of Native Americans by living among them. Peithmann had observed artifacts on the surface under or near the bluff at the Modoc site following road grading activities that resulted in the removal of ...