Main Page

Revision as of 22:04, 31 August 2023 by Alan.Myers (talk | contribs)

(diff) ← Older revision | Approved revision (diff) | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search

Welcome to ILSTRAT The Online Handbook of Illinois Stratigraphy

655 Articles • 2,859 Pages2 Active users • 18,034 Edits
Use the links to the right to navigate to the stratigraphic unit you are looking for, or search in several ways.
  • You can use the search box in the upper right-hand corner or the one below. You can search for the name of an article, or any term that appears in an article.
  • Within any article, you can use CTRL (or CMD) + F and search for a term in that article.

In most cases, the geologic information on each page is based on historical unit descriptions from either ISGS Bulletin 94, 95, or 104 (see About ILSTRAT). However, this online resource was not designed to be a static receptacle of previously published material. If you are a member of the geologic community, please consider contacting us to contribute to the efforts to update the contents of ILSTRAT-- either by adding new material like pictures or logs, updating geologic understanding with recent referenced works, or acting as editor/reviewer. In this way ILSTRAT can become an accurate reflection of current stratigraphic understanding in Illinois, driven by those most familiar with its intricacies.

Please have a look around and enjoy learning about the stratigraphy of Illinois.
If you have any questions, or would like to get a login to contribute to ILSTRAT, please contact us at


Cenozoic Erathem
Quaternary System
Holocene Series
Pleistocene Series
Tertiary System
Pliocene Series‏‎
Miocene Series
Oligocene Series
Eocene Series
Paleocene Series
Mesozoic‏ Erathem
Cretaceous System
Jurassic System
Triassic System
Paleozoic Erathem
Permian System
Carboniferous System
Pennsylvanian Subsystem
Mississippian Subsystem
Devonian System
Silurian System
Ordovician System
Cambrian System


Search:Holocene SeriesSearch:Pleistocene SeriesSearch:Pliocene SeriesMiocene SeriesOligocene SeriesSearch:Eocene SeriesSearch:Paleocene SeriesSearch:Quaternary SystemSearch:Tertiary SystemSearch:Cenozoic ErathemSearch:Mesozoic ErathemSearch:Cretaceous SystemJurassic SystemTriassic SystemPermian SystemSearch:Pennsylvanian SubsystemSearch:Paleozoic ErathemCarboniferous SystemSearch:Mississippian SubsystemSearch:Devonian SystemSearch:Silurian SystemSearch:Ordovician SystemSearch:Cambrian SystemSearch:Precambrian ErathemSearch:PhanerozoicMainpagetime.jpg
About this image