USGS Open-File Report 2010-1061: Revised Subsurface Stratigraphic Framework of the Fort Union and Wasatch
Formations, Powder River Basin, Wyoming and Montana

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April 19, 2010
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Changes were made to the PRB_CROSS_SECTION_ELEV table of the PRB_STRAT_DB.mdb.
The "TOP_ELEV_FT" and "BOTTOM_ELEV_FT" values for coal and sandstone beds were previously inverted for wells 
in cross-sections D-D', O-O', and P-P'. The issue was corrected by replacing the values in the "TOP_ELEV_FT" 
with those in the "BOTTOM_ELEV_FT" field and the "BOTTOM_ELEV_FT" values for those in the "TOP_ELEV_FT" field 
for the wells in the affected cross sections mentioned above.

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May 24, 2010
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Updates were applied to the "PRB_CROSSS_SECTION_ELEV" table of the PRB_STRAT_DB.mdb.
The fields "TOP_ELEV_FT" and  "BOTTOM_ELEV_FT"  in the above mentioned table were modified so that for every 
keywell in cross-section the top and bottom elevations of the coal beds were equal.