This Benchmark is easily located - it is embedded in the sidewalk on the southeast corner of Elm and Main in Lamar, Co.
From the datasheet:
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"JJ0225 ***********************************************************************
JJ0225 DESIGNATION - C 38
JJ0225 PID - JJ0225
JJ0225 STATE/COUNTY- CO/PROWERS
JJ0225 USGS QUAD - LAMAR EAST (1985)
JJ0225
JJ0225 *CURRENT SURVEY CONTROL
JJ0225 ___________________________________________________________________
JJ0225* NAD 83(1986)- 38 05 11. (N) 102 37 07. (W) SCALED
JJ0225* NAVD 88 - 1102.666 (meters) 3617.66 (feet) ADJUSTED
JJ0225 ___________________________________________________________________
JJ0225 GEOID HEIGHT- -23.25 (meters) GEOID99
JJ0225 DYNAMIC HT - 1101.611 (meters) 3614.20 (feet) COMP
JJ0225 MODELED GRAV- 979,635.1 (mgal) NAVD 88
JJ0225
JJ0225 VERT ORDER - FIRST CLASS II
JJ0225
JJ0225.The horizontal coordinates were scaled from a topographic map and have
JJ0225.an estimated accuracy of +/- 6 seconds.
JJ0225
JJ0225.The orthometric height was determined by differential leveling
JJ0225.and adjusted by the National Geodetic Survey in June 1991.
JJ0225
JJ0225.The geoid height was determined by GEOID99.
JJ0225
JJ0225.The dynamic height is computed by dividing the NAVD 88
JJ0225.geopotential number by the normal gravity value computed on the
JJ0225.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45
JJ0225.degrees latitude (G = 980.6199 gals.).
JJ0225
JJ0225.The modeled gravity was interpolated from observed gravity values.
JJ0225
JJ0225; North East Units Estimated Accuracy
JJ0225;SPC CO S - 466,270. 1,167,130. MT (+/- 180 meters Scaled)
JJ0225
JJ0225 SUPERSEDED SURVEY CONTROL
JJ0225
JJ0225 NGVD 29 - 1102.104 (m) 3615.82 (f) ADJ UNCH 1 2
JJ0225
JJ0225.Superseded values are not recommended for survey control.
JJ0225.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.
JJ0225.See file dsdata.txt to determine how the superseded data were derived.
JJ0225
JJ0225_MARKER: DB = BENCH MARK DISK
JJ0225_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT
JJ0225_STAMPING: 3615.820 C 38 1933
JJ0225_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO
JJ0225+STABILITY: SURFACE MOTION
JJ0225
JJ0225 HISTORY - Date Condition Recov. By
JJ0225 HISTORY - 1933 MONUMENTED CGS
JJ0225 HISTORY - 1953 GOOD USGS
JJ0225 HISTORY - 1968 GOOD NGS
JJ0225 HISTORY - 1985 GOOD NGS
JJ0225
JJ0225 STATION DESCRIPTION
JJ0225
JJ0225''DESCRIBED BY US GEOLOGICAL SURVEY 1953
JJ0225''AT LAMAR.
JJ0225''AT LAMAR, PROWERS COUNTY, AT THE COUNTY COURTHOUSE, IN THE NORTHWEST
JJ0225''CORNER OF THE YARD, 108 FEET NORTHWEST OF THE NORTHWEST CORNER OF
JJ0225''THE COURTHOUSE, AT THE INTERSECTION OF ELM AND MAIN STREETS, 16.8
JJ0225''FEET EAST OF THE EAST CURB OF MAIN STREET, AND 10.9 FEET SOUTH OF
JJ0225''THE SOUTH CURB OF ELM STREET. A STANDARD DISK, STAMPED 3615.820 C
JJ0225''38 1933 AND SET IN THE TOP OF A CONCRETE POST.
JJ0225
JJ0225 STATION RECOVERY (1968)
JJ0225
JJ0225''RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1968
JJ0225''RECOVERED IN GOOD CONDITION.
JJ0225
JJ0225 STATION RECOVERY (1985)
JJ0225
JJ0225''RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1985
JJ0225''RECOVERED IN GOOD CONDITION. NOTE--THE MONUMENT IS NOW SURROUNDED BY
JJ0225''AND FLUSH WITH A SIDEWALK. ADD--0.3 M (1.0 FT) EAST OF A CONCRETE
JJ0225''PLANTER."