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IMS-28 map and this companion site portray geologic information for educational purposes. At any given site in any map area, site-specific data could give results that differ from those shown here. This publication cannot replace site-specific investigations by qualified practitioners.

The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. This disclaimer applies both to individual use of the data and aggregate use with other data. If you are interested in a fuller version of this compilation that you can manipulate using your own GIS software, we strongly recommend that you acquire OGDC-5 from DOGAMI (see below). The Oregon Department of Geology and Mineral Industries shall not be held liable for improper or incorrect use of the data described and/or contained herein. Data are not intended for site-specific investigations.

DOGAMI reserves the right to update data on this web site without notification as new information becomes available.

  • Buy "Oregon: A Geologic History" (IMS-28) poster - 50-inch-wide x 58-inch-tall map printed on heavy paper. $15.
  • Buy OGDC-5 DVD - statewide coverage; requires GIS software to view spatial data; a tabular data browser is included on the DVD. The map units depicted in IMS-28 derive from this compilation.
  • View OGDC-3 interactive map - view interactive map that contains data through OGDC 3, includes the NE, SE, and Central portion of the state.
  • View/download 150-dpi IMS-28 map PDF.