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Details for Benchmark: JT0960

N 38° 05.067 W 122° 57.483 (NAD 83)

Altitude: 61.93

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

Location:
In MARIN county, CA View Original Datasheet
Designation:
X 477
Marker Type:
bench mark disk
Setting:
set into the top of a round concrete monument
Stability:
May hold, but of type commonly subject to surface motion.

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a piece of rebar that you can see from the road is the witness post

[Photos:]
photoIMG_0424

Found this along the side of the road relatively easily. Vegegation is sparser here so benchmark was more visible.

[Photos:]
photoJT0960.jpg
photoJT0960 Location.jpg

Documented History (by the NGS)

01/01/1951 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1951 6 MI N FROM POINT REYES. 6.0 MILES NORTH OF THE POINT REYES GRAMMAR SCHOOL, ABOUT 0.3 MILES SOUTHWEST OF THE ENTRANCE TO A RANCH, 204.0 FEET SOUTH OF THE SOUTHWEST CORNER OF A SMALL WOODEN BRIDGE, 24.0 FEET WEST OF THE CENTER LINE OF THE HIGHWAY, 12.7 FEET NORTH OF A POWER POLE, 2.4 FEET EAST OF A FENCE LINE, 2.0 FEET SOUTH OF A WITNESS POST, 1.0 FEET HIGHER THAN THE HIGHWAY, AND SET IN THE TOP OF A CONCRETE POST PROJECTING 0.4 FEET.
01/01/1972 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1972 RECOVERED IN GOOD CONDITION.
01/01/1985 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1985 NOTE: PROJECTS 0.75 FEET ABOVE GROUND LEVEL. NO WITNESS POST.
01/01/1987 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1987 RECOVERED IN GOOD CONDITION. A NEW TO REACH FOLLOWS. 11.7 KM (7.25 MI) SOUTHWESTERLY ALONG SIR FRANCIS DRAKE HIGHWAY FROM THE POST OFFICE IN INVERNESS. CHANGE--2.4 FEET EAST OF A FENCE, TO 1.4 M (4.6 FT) EAST OF A FENCE, AND THE MARK NOW PROJECTS 0.20 M (0.7 FT) ABOVE THE GROUND SURFACE.

Control Text

  • The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991.
  • The geoid height was determined by GEOID99.
  • The dynamic height is computed by dividing the NAVD 88 geopotential number by the normal gravity value computed on the Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 degrees latitude (G = 980.6199 gals.).
  • The modeled gravity was interpolated from observed gravity values.

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