These are some tough markers to photograph, but they are there and can be found.
If you are going to visit it - make sure you REALLY find it. This is a subtle benchmark that needs a long lens to see it. Shoot it from the opposite side of the canyon. There is no way to get to the top of the canyon walls for an up-close shot (unless you work for the government).
From the NGS Datasheet: (
visit link)
GR1851 DESIGNATION - NORTH BASE
GR1851 PID - GR1851
GR1851 STATE/COUNTY- AZ/MOHAVE
GR1851 COUNTRY - US
GR1851 USGS QUAD - HOOVER DAM (1997)
GR1851
GR1851 *CURRENT SURVEY CONTROL
GR1851 ______________________________________________________________________
GR1851* NAD 83(1992) POSITION- 36 00 52.60353(N) 114 44 13.97599(W) ADJUSTED
GR1851_U.S. NATIONAL GRID SPATIAL ADDRESS: 11SQV0391887937(NAD 83)
GR1851
GR1851_MARKER: DS = TRIANGULATION STATION DISK
GR1851_SETTING: 0 = UNSPECIFIED SETTING
GR1851_STABILITY: D = MARK OF QUESTIONABLE OR UNKNOWN STABILITY
GR1851_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR
GR1851+SATELLITE: SATELLITE OBSERVATIONS - August 10, 2014
GR1851
GR1851 HISTORY - Date Condition Report By
GR1851 HISTORY - 1935 MONUMENTED BOR
GR1851 HISTORY - 1990 GOOD USPSQD
GR1851 HISTORY - 20140810 GOOD GEOCAC
GR1851
GR1851 STATION DESCRIPTION
GR1851
GR1851'DESCRIBED BY US BUREAU OF RECLAMATION 1935
GR1851'STATION IS A THREE-SIDED CONCRETE PIER ABOUT 1-1/2 FEET HIGH,
GR1851'LOCATED ON A ROCK WALL ABOUT 150 FEET DOWNSTREAM FROM THE
GR1851'ARIZONA END OF HOOVER DAM, WITH A STANDARD USC AND GS STATION
GR1851'DISK, THE CENTER OF WHICH HAS BEEN GROUND DOWN TO RECEIVE A
GR1851'FINE SCRATCH MARK.
GR1851
GR1851 STATION RECOVERY (1990)
GR1851
GR1851'RECOVERY NOTE BY US POWER SQUADRON 1990 (MG)
GR1851'RECOVERED IN GOOD CONDITION.
GR1851
GR1851 STATION RECOVERY (2014)
GR1851
GR1851'RECOVERY NOTE BY GEOCACHING 2014 (LPC)
GR1851'RECOVERED IN GOOD CONDITION.