Subsurface Rock Correlation Diagram

Click for a PDF table of all unit names, their approximate geographic extents, and references (bureau publications that include the units). Maps referenced in the PDF table can be accessed through the smaller “list of units” tables that are linked to from the bottom of each system(s) page (e.g., Permian-Mississippian page).

View correlation diagram as a PDF document (2.07 MB; opens in a new window) 


Chart legend showing rock types and associated oil and gas resources.












Subsurface Stratigraphic Correlation Diagram. The chart is divided into four sections by age: Permian to Mississippian, Devonian, Silurian to Ordovician, and Cambrian to Precambrian.