Details for Benchmark: MA1136
N 41° 29.167 W 079° 23.883 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In FOREST county, PA View Original Datasheet
- Y 88
- Marker Type:
- bench mark disk
- set into the top of a round concrete monument
- May hold, but of type commonly subject to surface motion.
Benchmarks may be on private property or in dangerous locations. Obey local laws. By using the services on Geocaching.com you agree to this disclaimer.
Documented History (by the NGS)
|01/01/1935 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1935
5.4 MI E FROM TIONESTA. ABOUT 5.4 MILES EAST ALONG STATE HIGHWAY 66 FROM THE COUNTY COURTHOUSE AT TIONESTA, FOREST COUNTY, AT STATION 2-50+15, AT THE JUNCTION OF A GRAVEL ROAD LEADING UPHILL TO AN OIL TANK, ABOUT 60 FEET EAST OF A CONCRETE BRIDGE MARKED BM 1084.6, AT THE NORTHEAST SIDE, 40 FEET SOUTH OF THE CENTER LINE OF THE HIGHWAY, 21 FEET WEST OF THE CENTER LINE OF THE ROAD, AND ABOUT 2 FEET HIGHER THAN THE ROADWAY. A STANDARD DISK, STAMPED Y 88 1935 AND SET IN THE TOP OF A CONCRETE POST PROJECTING ABOUT 8 INCHES ABOVE GROUND. NOTE-- THE DESCRIPTIONS FOR THE MARKS ON THIS LINE REFER TO THE 1935 LOCATION OF STATE HIGHWAYS 66 AND 666. THE PRESENT LOCATION OF THESE HIGHWAYS HAS BEEN RELOCATED DUE TO HIGH WATER OF THE TIONESTA DAM, THEREFORE MARKS FROM BM 4-58+70 TO Y-78 MAY OR MAY NOT BE RECOVERABLE DURING TIMES OF LOW WATER OF THE RESERVOIR. NOTE-- THE LOCATION OF STATE HIGHWAYS 66 AND 666, HAVE BEEN RELOCATED DUE TO HIGH WATER OF THE TIONESTA DAM, THEREFORE THE MARK MAY OR MAY NOT BE RECOVERABLE DURING TIMES OF LOW WATER OF THE RESERVOIR.
- 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.