Urbana in Champaign County, Illinois — The American Midwest (Great Lakes)

Cyclothems

Photographed by Duane and Tracy Marsteller, May 28, 2023

1. Cyclothems Marker

Inscription.
In 1932, Harold R. Wanless introduced the term cyclothem to describe the succession of sedimentary rock layers found in coal-bearing formations. The understanding of cyclothems remains an indispensable tool for predicting the location of coal deposits and for defining the processes by which sea levels change.

Erected by University of Illinois.

Topics and series. This historical marker is listed in these topic lists: Education • Environment • Science & Medicine. In addition, it is included in the University of Illinois series list. A significant historical year for this entry is 1932.

Location. 40° 6.543′ N, 88° 13.57′ W. Marker is in Urbana, Illinois, in Champaign County. It can be reached from South Mathews Avenue 0.1 miles south of West Green Street, on the right when traveling south. Marker is on the south side of the Natural History Building, near the Woolly Mammoth statue. Touch for map. Marker is in this post office area: Urbana IL 61801, United States of America. Touch for directions.

Regionally, this marker is in Central Illinois.

It is also in the American Midwest

and in the Corn Belt.

Globally, it is in North America,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once the territory of the Mississippian Culture

and also the Northwest Territory.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Illite and Clay Mineralogy (within shouting distance of this marker); Understanding Photosynthesis (about 300 feet away, measured in a direct line); Natural History Building (about 300 feet away); Former Site of the University of Illinois College of Medicine at Urbana-Champaign

Paid Advertisement

Click or scan to see
this page online

(about 300 feet away); Nuclear Magnetic Resonance (about 300 feet away); Measuring Molecular Structure (about 400 feet away); Archaea (about 500 feet away); John Milton Gregory (about 600 feet away). Touch for a list and map of all markers in Urbana.

Also see . . .
1. Cyclothems. Wikipedia entry (Submitted on August 7, 2023, by Larry Gertner of New York, New York.)

2. Memorial to Harold Rollin Wanless 1898-1970. Geological Society of America PDF (Submitted on June 4, 2025, by Larry Gertner of New York, New York.)

Carboniferous cyclothems at Scremerston, Northumberland image. Click for full size.

via Friday Fold, unknown

2. Carboniferous cyclothems at Scremerston, Northumberland

Harold R. Wanless image. Click for full size.

via University of Illinois, unknown

3. Harold R. Wanless

Photographed by Duane and Tracy Marsteller, May 28, 2023

4. Cyclothems Marker

Marker is by the tree on the right.

Credits. This page was last revised on June 4, 2025. It was originally submitted on June 8, 2023, by Duane and Tracy Marsteller of Murfreesboro, Tennessee. This page has been viewed 367 times since then and 25 times this year. Photos: 1. submitted on June 8, 2023, by Duane and Tracy Marsteller of Murfreesboro, Tennessee. 2, 3. submitted on August 7, 2023, by Larry Gertner of New York, New York. 4. submitted on June 8, 2023, by Duane and Tracy Marsteller of Murfreesboro, Tennessee.