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Details for Benchmark: HV2660

N 38° 45.917 W 077° 22.017 (NAD 83)

Altitude: 323.45

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

Location:
In FAIRFAX county, VA View Original Datasheet
Designation:
PTS 3 USGS
Marker Type:
pipe cap
Setting:
set into the top of a metal pipe driven into the ground
Stability:
Mark of questionable or unknown stability.

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I didn't expect much luck with a 90+ year old iron pipe. Not sure what the pipe cap would look like. No mention of stamping, so I suppose it't just a plain end cap?

The stucco house -- or the shell of a house that appears to be the building mentioned -- is on blocks a few yards away from its apparent previous location. I did examine an area measured from the centerlines per the description, but I found nothing.

You may have better luck, especially if you come equipped with a metal detector.

[Photos:]
photoArea, unfound PTS 3 USGS (HV2660), Fairfax Co., VA
General area described in 1941 as site of unfound mark would seem to be to the left and in front of the pipeline marker. Note house on blocks in distance.

Documented History (by the NGS)

01/01/1911 by USGS (MONUMENTED)
01/01/1941 by CGS (GOOD)
DESCRIBED BY COAST AND GEODETIC SURVEY 1941 1.6 MI SE FROM CLIFTON. 1.6 MILES SOUTHEAST OF THE RAILROAD CROSSING IN CLIFTON ALONG COUNTY HIGHWAY NO. 646, AT THE INTERSECTION OF COUNTY HIGHWAYS NO. 645 AND 646, 19 FEET SOUTHWEST OF THE CENTERLINE OF HIGHWAY NO. 645, 36 FEET NORTHWEST OF THE CENTERLINE OF HIGHWAY NO. 646, 74 FEET SOUTHEAST OF THE NORTHEAST CORNER OF SMALL STUCCO HOUSE, IRON PIPE WITH U.S. GEOLOGICAL SURVEY CAP PROJECTING 10 INCHES ABOVE GROUND.

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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