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Details for Benchmark: JC1817

N 38° 30.317 W 090° 37.000 (NAD 83)

Altitude: 466.6

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

Location:
In ST LOUIS county, MO View Original Datasheet
Designation:
60 M
Marker Type:
survey 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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Found generally as described. The NGS datasheet has now been corrected to the following HH2 coordinates: 38 37 20.8, -090 17 19.0. (I measured the coordinates as 38 37 20.5, -090 17 19.3.)

Also, Although the school still has signs for its previous name, Gratiot, it is now the Records Center/Archives and International Education Consortium, according to the large sign on the building.

The somewhat weathered USGS disk is mounted on a concrete post, which projects from a slanted surface of mortared flat rock between a retaining wall and iron fence along the Manchester Avenue sidewalk and a chain link fence above, which surrounds the school parking lot.

[Photos:]
photoCloseup, 60 M (JC1817), St. Louis, MO
photoArea, 60 M (JC1817), St. Louis, MO
View to the west along Manchester Avenue. Yellow box highlights location of disk.
photoArea, 60 M (JC1817), St. Louis, MO
View to the east along Manchester Avenue. Note Hampton Avenue overpass.

Found this one in fair condition.

[Photos:]
photo60 M

Found this during a group benchmark hunt between sessions at A Benchmarking Event. The previous descriptions and pictures are good. Coordinates from my Etrex were 38 37.347 N 90 17.317 W

Found this one between speeches during "A Benchmark Event".

During the A Benchmark Event today,rogbarn,happycycler,me,and gbrotz.
Thanks guys.

[Photos:]
photoJC1817 60 M
While at the Benchmark Event today.

Would never have found this one without Happycycler and Rogbarn's work. Thanks!

N 38° 37.351 W 090° 17.315

Found this one with a LOT of help from rogbarn. He discovered that the location was seriously in error. The description is good but the lat. / lon. are 19.5 miles away at 245.5 degrees -- out near Times Beach.

The concrete monument sits out like a sore thumb from the limestone flagstone pavement on the slope from the school playground to the retaining wall. The disk is somewhat corroded but the designation and the date can be read.

The lat. & lon. are from a quick reading of my handheld recreational Magellan GPS.

[Photos:]
photoJC1817 (60 M) near Gratiot School
designation 60 M & date are hard to read in my photo
photoJC1817 monument & school sign
photosign & school building
photostreet signs
photoJC1817 without crayon enhancement

Documented History (by the NGS)

1/1/1931 by USGS (MONUMENTED)
8/27/1984 by USGS (GOOD)
DESCRIBED BY US GEOLOGICAL SURVEY 1984 IN THE WEST PART OF ST LOUIS, IN THE NORTHWEST ANGLE OF THE INTERSECTION OF HAMPTON AND MANCHESTER AVENUES, AT THE SOUTHEAST CORNER OF THE GROUNDS OF THE GRATIOT SCHOOL, 14.0 M (45.9 FT) WEST FROM THE CENTERLINE OF HAMPTON AVENUE, 12.65 M (41.50 FT) NORTH FROM THE CENTERLINE OF MANCHESTER AVENUE, 4.83 M (15.85 FT) WEST-NORTHWEST FROM THE SOUTHEAST CORNER OF A CONCRETE RETAINING WALL, 3.20 M (10.50 FT) SOUTHWEST FROM A METAL SIGNPOST FOR THE GRATIOT SCHOOL.
4/27/1992 by MOGS (GOOD)
RECOVERY NOTE BY MISSOURI GEODETIC SURVEY 1992 RECOVERED IN GOOD CONDITION.
4/8/1995 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1995 RECOVERED IN GOOD CONDITION.
2/6/1999 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1999 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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