Statewide and regional correlation charts, lexicons, and other stratigraphic resources (1890-present)

To compile this National lexicon of geologic names, we rely on authoritative, published summaries and compendiums including regional correlation charts and lexicons, as well as the many thousand individual scientific reports and maps that have been published since the 1800's. In particular, correlation charts are invaluable because they graphically illustrate the regional stratigraphy, helping each of us to better understand the areal extent of each geologic unit, and the uncertainties in stratigraphic interpretations.

In Geolex, the stratigraphic interpretations contained in >10,000 pertinent publications are listed on the Unit Reference Summary pages. These publications are supplemented by references and notes contained in the Geologic Names Committee Archives, which are linked from the Geolex entries for each geologic name. That level of detail is essential for the stratigrapher, but it also is helpful to step back and see the "bigger picture." For example, which geologic units occur and in what sequence, along a cross section of the Rocky Mountains through the states of Colorado and New Mexico? Or, for the state of Alabama, where can I find a concise, authoritative summary of the stratigraphy?

This Web page provides access to a select number of those state and regional compilations, in order to: (1) serve as a general resource for the field geologist and stratigrapher, and (2) provide the interested lay-person with a short list of significant summaries. We used the following guidelines to determine the content of this page:

• Include publications found most useful for compiling Geolex and the previous U.S. lexicons (USGS Bulletins 896 and 1200)
• The list of resources for each state must be manageable in length -- that is, a few selected references rather than dozens. When applied to larger states with complex geology (e.g., Alaska, California, Nevada), this is particularly challenging
• Emphasize currently recognized stratigraphy, but also include older compilations of significant historical value as well as those focusing on a particular time period
• Restrict the list to publications that are available for viewing online without a subscription.

Bearing in mind these guidelines, we sincerely request your guidance and comments on this site and its content.