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Details for Benchmark: HS3492

N 37° 40.783 W 121° 42.333 (NAD 83)

Altitude: 637.8

Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)

Location:
In ALAMEDA county, CA View Original Datasheet
Designation:
B 738 RESET 1957
Marker Type:
bench mark disk
Setting:
light structures
Stability:
Mark of questionable or unknown stability.

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I teamed with a non-cacher who was interested in locating this Benchmark. Since I did not have my GPS, I did a little reverse coordinate searching and the two of us found it on our lunch break.
If you can access this area, you will NOT be in harms way when you find it.
The Benchmark is in good shape.

Took a little (re) reading of the original description - this one is 178 feet away from the given coordinates (HINTS: it is within the LLNL fence)

Documented History (by the NGS)

01/01/1957 by CGS (MONUMENTED)
01/01/1958 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1958 6.3 MI SW FROM ALTAMONT. 3.5 MILES SOUTHWEST ALONG THE SOUTHERN PACIFIC COMPANY RAILROAD FROM THE ABANDONED STATION AT ALTAMONT, THENCE 2.3 MILES SOUTH ALONG GREENVILLE ROAD, THENCE 0.5 MILE WEST ALONG EAST AVENUE, IN R2E T3S S12, AT THE U.S. ATOMIC ENERGY COMMISSION, AT THE MAIN GATE, IN THE TOP OF THE NORTHWEST CORNER OF A CONCRETE COVER FOR A MANHOLE, 25.6 FEET WEST OF THE WEST CURB OF A AVENUE, 18.2 FEET SOUTH OF THE SOUTHEAST CORNER OF BUILDING 133 (SECURITY OFFICE), 11.8 FEET NORTH OF THE NORTH CURB OF AN ACCESS ROAD LEADING WEST, 11 FEET NORTH OF A FIRE HYDRANT, 2.6 FEET NORTHWEST OF THE NORTHWEST EDGE OF AN IRON MANHOLE COVER DOOR, AND ABOUT LEVEL WITH THE SIDEWALK.
01/01/1960 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1960 RECOVERED IN GOOD CONDITION.
01/01/1989 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1989 (LK) RECOVERED IN GOOD CONDITION.

Control Text

  • The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
  • The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.
  • The geoid height was determined by GEOID99.

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