DATABASE STRUCTURE  -- ArcInfo and ArcView ==========
There are two coverages (root name = denv) and three additional info files.
This GIS database includes related look-up tables, which store detailed attribute information.  Arc/Info relates for each coverage are saved in a file named <covername>.rel.  Use the RELATE command with the restore argument at the arc prompt to make the relates active.  Alternatively, in Arctools, use the Relate environment:  open dialog in the Manage - Relates flyout menu under the Arctools menu to make the relates active.
denvpoly coverage: contains all contact lines and labelpoints for each geologic polygon.  In the denvpoly.pat INFO file the LABEL item indicates the rock unit label (abbreviation) used to label the unit on the map.  The DESC item contains the formal or informal unit name.  The SOURCE item contains the numeric code used to identify the data source for the rock unit.  The SYMBOL item contains the shadeset symbol number used by ArcInfo to plot a filled/shaded polygon.  The symbol numbers in this coverage refer to the color524.shd shadeset.
In the coverage's denvpoly.aat INFO file the NAME item contains the name given to the structural feature.  The SOURCE item contains the numeric code used to identify the data source for the structural feature.  The SYMBOL item contains the lineset symbol number used by ArcInfo to plot a line.  The symbol numbers in this coverage refer to the geol_sfo.lin lineset.
In the the coverages's denvpoly.ref INFO file the SOURCE item lists the numeric code used to identify the data source.  The scale item list the scale of the source map.  (This value is the denominator of the proportional fraction that identifies the scale of the map that was digitized or scanned to produce the digital map.)  The AUTHORS item lists the author(s) or compiler(s) of source map entered as last name, first name or initial, and middle initial.  The YEAR item lists the source (map) publication date.  The REFERENCE item lists the remainder of the reference in USGS reference format.
The INFO structure of these files is listed below:
>DENVPOLY.PAT:
>
>COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME
>    1  AREA                   8    18     F      5
>    9  PERIMETER              8    18     F      5
>   17  DENVPOLY#              4     5     B      -
>   21  DENVPOLY-ID            4     5     B      -
>   25  SOURCE                 4     4     I      -
>   29  LABEL                 10    10     C      -
>   39  DESC                 123   123     C      -
>  162  SYMBOL                 3     3     I      -
>DENVPOLY.AAT:
>
>COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE  N.DEC  ALTERNATE NAME
>    1  FNODE#                 4     5     B      -
>    5  TNODE#                 4     5     B      -
>    9  LPOLY#                 4     5     B      -
>   13  RPOLY#                 4     5     B      -
>   17  LENGTH                 8    18     F      5
>   25  DENVPOLY#              4     5     B      -
>   29  DENVPOLY-ID            4     5     B      -
>   33  NAME                  30    30     C      -
>   63  SOURCE                 4     4     I      -
>   67  SYMBOL                 3     3     I      -
>DENVPOLY.REF:
>
>COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME
>    1  SOURCE                 4     4     I      -
>    5  SCALE                  8     8     I      -
>   13  AUTHORS              200   200     C      -
>  213  YEAR                   4     4     I      -
>  217  REFERENCE            250   250     C      -
>
>  Unique values of NAME in DENVPOLY.AAT: contact, neat, water
denvline coverage: contains faults.  In the denvline.aat INFO file the NAME item indicates the name given to the structural feature.
In the the coverages's denvline.ref INFO file the SOURCE item lists the numeric code used to identify the data source.  The scale item list the scale of the source map.  (This value is the denominator of the proportional fraction that identifies the scale of the map that was digitized or scanned to produce the digital map.)  The AUTHORS item lists the author(s) or compiler(s) of source map entered as last name, first name or initial, and middle initial.  The YEAR item lists the source (map) publication date.  The REFERENCE item lists the remainder of the reference in USGS reference format.
The INFO structure of these files is listed below:
>DENVLINE.AAT:
>
>COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME
>    1  FNODE#                 4     5     B      -
>    5  TNODE#                 4     5     B      -
>    9  LPOLY#                 4     5     B      -
>   13  RPOLY#                 4     5     B      -
>   17  LENGTH                 8    18     F      5
>   25  DENVLINE#              4     5     B      -
>   29  DENVLINE-ID            4     5     B      -
>   33  NAME                  30    30     C      -
>   63  SOURCE                 4     4     I      -
>   67  SYMBOL                 3     3     I      -
>DENVLINE.REF:
>
>COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME
>    1  SOURCE                 4     4     I      -
>    5  SCALE                  8     8     I      -
>   13  AUTHORS              200   200     C      -
>  213  YEAR                   4     4     I      -
>  217  REFERENCE            250   250     C      -
>
>  Unique values of NAME in DENVLINE.AAT: High-angle reverse fault
>Database root name: denv
>LABEL AND DESCRIPTION FOR GEOLOGIC UNITS MAPPED
>LABEL              DESC
>afa      Alluvial-fan deposit
>cac      Arkosic loamy colluvium and sheetwash alluvium
>cacb     Bouldery phase of arkosic loamy colluvium
>xch      Clayey, calcareous disintegration residuum
>dba      Crystalline-clast deposits
>dbd      Mixed-lithology-clast deposits
>asa      Alluvial sand, silt, clay, and gravel (post-Piney
>         Creek alluvium, Piney Creek Alluvium,and pre-Piney Creek alluvium
>ed       Stabilized dune sand
>es       Eolian sand
>jea      Slump-block, earthflow, and mudflow landslide deposits
>ccd      Calcareous clayey colluvium
>ccm      Andesitic clayey colluvium
>caa      Andesitic loamy colluvium
>clx      Clay loam colluvium
>csk      Grus, crystalline-clast colluvium, rock outcrop, and alluvium
>csm      Tuffaceous colluvium
>cgc      Gneiss- and granite-clast gravelly colluvium
>cgh      Arkose-clast loamy colluvium
>cbh      Blocky sedimentary-rock colluvium
>cbm      Carbonate-clast loamy colluvium
>cbs      Rhyolite- and andesite-clast colluvium
>cbu      Mixed-lithology blocky colluvium
>xlu      Feldspathic loamy disintegration residuum
>xlv      Loamy disintegration residuum, eolian sand, and sheetwash alluvium
>xsa      Feldspathic quartz-sand disintegration residuum
>xgb      Latite-clast disintegration residuum
>jbc      Bouldery crystalline-rock landslide deposit
>xsg      Feldspathic quartz-sand disintegration residuum
>elb      Loess (Peoria Formation)
>tbg      Crystalline-clast bouldery till
>tbj      Mixed-lithology-clast bouldery till
>ggq      Outwash sand and gravel (outwash of Bull Lake, Pinedale, and post-Pinedale ages)
>ags      Alluvial sand, silt, clay and gravel (Louviers and Slocum
>         Alluviums, undivided; late middle Pleistocene)
>tbk      Bouldery till (till of pre-Bull Lake glaciations)
>gge      Outwash sand and gravel (outwash of pre-Bull Lake glaciations)
>agm      Alluvium gravel and sand (Verdos and Rocky Flats Alluviums,
>         undivided; early middle Pleistocene and early Pleistocene)
>pga      Pediment gravel
>cra      Hogback and rangefront colluvium, alluvium, and rock outcrop complex
>QTdd     Diamicton
>R        Bedrock
>w        Open water

http://pubs.usgs.gov/mf/2001/mf-2347/mf-2347pam.pdf