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Details for Benchmark: SU0984

N 47° 36.367 W 115° 04.549 (NAD 83)

Altitude: 6967

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

Location:
In SANDERS county, MT View Original Datasheet
Designation:
BIG HOLE
Marker Type:
NGS Benchmark
Setting:
setting not listed - see description
Stability:
Most reliable and expected to hold position/elevation well.

Reference Points

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Documented History (by the NGS)

01/01/1940 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1940 (ANS) THE STATION IS ON THE HIGHEST POINT OF BIG HOLE PEAK WHICH IS THE HIGHEST IN THE VICINITY AND THE FIRST PEAK W (0.3 MILE) OF BIG HOLE LOOKOUT HOUSE AND ABOUT 13 MILES E OF THOMPSON FALLS AND ABOUT 14-1/2 MILES NW OF PLAINS. THE TOP OF THE PEAK HAS A FEW LOW TREES TO THE W AND A VERY SHARP BLUFF TO THE N AND E. THE STATION MARK IS A STANDARD BRONZE DISK WEDGED IN A DRILL HOLE IN OUTCROPPING BEDROCK AND ABOUT 8 FEET W OF THE E EDGE OF BLUFF, FLUSH WITH THE GROUND. IT IS STAMPED BIG HOLE 1940. REFERENCE MARK NO. 1 IS A STANDARD BRONZE DISK WEDGED IN A DRILL HOLE IN OUTCROPPING BEDROCK, ABOUT 1 FOOT W OF THE E EDGE OF BLUFF, FLUSH WITH THE GROUND, 1 FOOT BELOW THE STATION. IT IS STAMPED BIG HOLE NO. 1, 1940. REFERENCE MARK NO. 2 IS A STANDARD BRONZE DISK WEDGED IN A DRILL HOLE IN OUTCROPPING BEDROCK, ABOUT 1 FOOT W OF THE E EDGE OF BLUFF, FLUSH WITH THE GROUND, 1 FOOT BELOW THE STATION. IT IS STAMPED BIG HOLE NO. 2, 1940. THE AZIMUTH MARK IS A STANDARD U.S.G.S. BENCH MARK SET IN OUTCROPPING BEDROCK, 10 FEET W OF THE W SIDE OF BIG HOLE LOOKOUT HOUSE, FLUSH WITH THE GROUND. IT IS STAMPED BIG HOLE. THE STATION IS REACHED FROM THE POST OFFICE IN PLAINS BY GOING W ON STATE HIGHWAY 3 FOR 7.3 MILES TO WHITE SCHOOLHOUSE ON THE LEFT (S). CONTINUE W FOR 0.35 MILE TO A DIRT ROAD LEADING RIGHT (N). TURN N ONTO THIS DIRT ROAD AND GO 0.2 MILE TO MR. P. GRAYS BARN WHICH IS THE END OF TRUCK TRAVEL. FROM HERE PACK N ALONG THE W SIDE OF MEADOW ON A TRACK ROAD AND THEN A TRAIL THROUGH THE WOODS FOR ABOUT 2 MILES TO A FORK IN THE TRAILS. TAKE CENTER FORK TRAIL WHICH IS NO. 368 AND POSTED BIG HOLE LOOKOUT 6-1/2 MILES AND FOLLOW THIS WELL TRAVELED AND MARKED TRAIL TO TOP OF MOUNTAIN AT THE LOOKOUT HOUSE. CONTINUE W ALONG TOP OF RIDGE ABOUT 0.3 MILE TO THE HIGHEST POINT AND STATION. WITH HORSES THE PACK IS ABOUT 4 HOURS AND AFOOT ABOUT 5 HOURS. THE TRAIL IS AN EASY GRADE THROUGHOUT. HEIGHT OF LIGHT ABOVE STATION MARK - 1-1/2 METERS.
01/01/1964 by USGS (GOOD)
RECOVERY NOTE BY US GEOLOGICAL SURVEY 1964 STATION MARK - - STANDARD USC AND GS DISK, STAMPED--- BIG HOLE 1940 ---, CEMENTED IN LEDGE ROCK.
01/01/1968 by CGS (GOOD)
RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1968 (LBG) THE STATION MARK, REFERENCE MARKS 1 AND 2, AND THE AZIMUTH MARK WERE RECOVERED IN GOOD CONDITION. THE DISTANCE AND THE DIRECTION TO THE REFERENCE MARKS COMPARED FAVORABLY WITH THE 1940 OBSERVATIONS. A COMPLETE NEW DESCRIPTION FOLLOWS. THE STATION IS LOCATED ABOUT 14-1/2 MILES NORTHWEST OF PLAINS, 13 MILES EAST OF THOMPSON FALLS ON THE HIGHEST POINT OF BIG HOLE PEAK WHICH IS THE NEXT PEAK WEST OF THE BIG HOLE LOOKOUT HOUSE. TO REACH THE STATION FROM THE POST OFFICE IN PLAINS, GO WEST ON U. S. HIGHWAY 10 A AND MONTANA STATE HIGHWAY 200 FOR 7.75 MILES TO A SIDE ROAD RIGHT AND SIGN WEEKSVILLE CREEK ROAD. TURN RIGHT AND GO NORTH ON A GRAVELED ROAD FOR 0.05 MILE TO A FORK. TAKE THE LEFT FORK AND GO NORTHERLY ON THE MAIN ROAD FOR 3.3 MILES TO A FORK, KEEP THE LEFT FORK AS PER SIGN BIG HOLE LOOKOUT 12, AND GO NORTHWESTERLY ON THE MAIN TRAVELED ROAD FOR 10.5 MILES TO A SIGN BIG HOLE LOOKOUT TRAIL NO 368, AND END OF TRUCK TRAVEL. HERE PACK WESTERLY AND NORTHERLY ON A WELL MARKED TRAIL FOR 2 MILES TO A FORK IN THE TRAIL AND SIGN BIG HOLE LOOKOUT 0.2 MILE. TAKE THE LEFT FORK UP HILL TO THE LOOKOUT HOUSE AND THE U. S. GEOLOGICAL SURVEY BENCH MARK THAT WAS USED FOR AN AZIMUTH MARK. HERE PACK WESTERLY ON TRAIL NO 371 FOR 0.3 MILE TO THE TOP OF THE NEXT PEAK TO THE WEST AND THE STATION. A THREE HOUR PACK ON A GOOD TRAIL. THE STATION MARK IS A STANDARD DISK STAMPED BIG HOLE 1940, CEMENTED IN A DRILL HOLE IN OUTCROPPING BED ROCK THAT IS FLUSH WITH THE GROUND SURFACE. IT IS ABOUT 8 FEET WEST OF THE EAST EDGE OF THE BLUFF. REFERENCE MARK 1 IS A STANDARD DISK STAMPED BIG HOLE NO 1 1940, CEMENTED IN A DRILL HOLE IN OUTCROPPING BEDROCK THAT IS FLUSH WITH THE GROUND SURFACE. IT IS 1 FOOT WEST OF THE EAST EDGE OF THE BLUFF AND ABOUT 1 FOOT LOWER THAN THE STATION. REFERENCE MARK 2 IS A STANDARD DISK STAMPED BIG HOLE NO 2 1940, CEMENTED IN A DRILL HOLE IN OUTCROPPING BEDROCK THAT IS FLUSH WITH THE GROUND SURFACE. IT IS 1 FOOT WEST OF THE EAST EDGE OF THE BLUFF AND 1 FOOT LOWER THAN THE STATION. THE AZIMUTH MARK IS A U. S. GEOLOGICAL SURVEY BENCH MARK DISK STAMPED BIG HOLE, CEMENTED IN A DRILL HOLE IN OUTCROPPING BEDROCK THAT IS FLUSH WITH THE GROUND SURFACE. IT IS 12 FEET NORTHWEST OF THE SOUTHWEST CORNER OF THE BIG HOLE LOOKOUT HOUSE. AIRLINE DISTANCE AND DIRECTION FROM NEAREST TOWN--13 MILES EAST OF THOMPSON FALLS.

Control Text

  • The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in July 1992.
  • The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.)
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • The geoid height was determined by GEOID99.

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