National Geodetic Survey, Retrieval Date = OCTOBER 6, 2001 HS5120 *********************************************************************** HS5120 DESIGNATION - MOUNT DIABLO HS5120 PID - HS5120 HS5120 STATE/COUNTY- CA/CONTRA COSTA HS5120 USGS QUAD - CLAYTON (1994) HS5120 HS5120 *CURRENT SURVEY CONTROL HS5120 ___________________________________________________________________ HS5120* NAD 83(1992)- 37 52 54.11201(N) 121 54 50.95799(W) ADJUSTED HS5120* NAVD 88 - 1177.7 (meters) 3864. (feet) VERTCON HS5120 ___________________________________________________________________ HS5120 EPOCH DATE - 1991.35 HS5120 LAPLACE CORR- 0.58 (seconds) DEFLEC99 HS5120 GEOID HEIGHT- -31.73 (meters) GEOID99 HS5120 HS5120 HORZ ORDER - FIRST HS5120 HS5120.The horizontal coordinates were established by classical geodetic methods HS5120.and adjusted by the National Geodetic Survey in March 1994. HS5120.The horizontal coordinates are valid at the epoch date displayed above. HS5120.The epoch date for horizontal control is a decimal equivalence HS5120.of Year/Month/Day. HS5120 HS5120.The NAVD 88 height was computed by applying the VERTCON shift value to HS5120.the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) HS5120 HS5120.The Laplace correction was computed from DEFLEC99 derived deflections. HS5120 HS5120.The geoid height was determined by GEOID99. HS5120 HS5120; North East Units Scale Converg. HS5120;SPC CA 3 - 654,282.499 1,875,605.240 MT 0.99993177 -0 51 56.8 HS5120;SPC CA 3 - 2,146,591.83 6,153,548.19 sFT 0.99993177 -0 51 56.8 HS5120;UTM 10 - 4,193,244.908 595,488.656 MT 0.99971230 +0 40 00.5 HS5120 HS5120: Primary Azimuth Mark Grid Az HS5120:SPC CA 3 - MOUNT DIABLO AZ MK 222 58 24.3 HS5120:UTM 10 - MOUNT DIABLO AZ MK 221 26 27.0 HS5120 HS5120|---------------------------------------------------------------------| HS5120| PID Reference Object Distance Geod. Az | HS5120| dddmmss.s | HS5120| MOUNT DIABLO RM 1 3.076 METERS 16304 | HS5120| MOUNT DIABLO AZ MK 2220627.5 | HS5120| MOUNT DIABLO RM 2 2.976 METERS 25314 | HS5120| HS5119 MOUNT DIABLO FLAGPOLE 1931 14.700 METERS 25412 | HS5120| HS5122 MOUNT DIABLO AVIATION BEACON 61.880 METERS 26109 | HS5120| MOUNT DIABLO RM 2 ECC 62.835 METERS 26205 | HS5120| MOUNT DIABLO RM 2.410 METERS 34550 | HS5120| MOUNT DIABLO AZ MK OLD 3501732.2 | HS5120|---------------------------------------------------------------------| HS5120 HS5120 SUPERSEDED SURVEY CONTROL HS5120 HS5120 NAD 83(1986)- 37 52 54.11230(N) 121 54 50.95535(W) AD(1984.00) 1 HS5120 NAD 27 - 37 52 54.38700(N) 121 54 47.10700(W) AD( ) 1 HS5120 NGVD 29 - 1176.9 (m) 3861. (f) VERT ANG HS5120 HS5120.Superseded values are not recommended for survey control. HS5120.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. HS5120.See file dsdata.txt to determine how the superseded data were derived. HS5120 HS5120_MARKER: DD = SURVEY DISK HS5120_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT HS5120_MARK LOGO: CGS HS5120_MAGNETIC: N = NO MAGNETIC MATERIAL HS5120_STABILITY: A = MOST RELIABLE AND EXPECTED TO HOLD HS5120+STABILITY: POSITION/ELEVATION WELL HS5120_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR HS5120+SATELLITE: SATELLITE OBSERVATIONS - July 15, 1992 HS5120 HS5120 HISTORY - Date Condition Report By HS5120 HISTORY - 1876 MONUMENTED CGS HS5120 HISTORY - 1852 GOOD CGS HS5120 HISTORY - 1935 GOOD CGS HS5120 HISTORY - 1938 GOOD CGS HS5120 HISTORY - 1946 GOOD CGS HS5120 HISTORY - 1948 GOOD CGS HS5120 HISTORY - 1951 GOOD CGS HS5120 HISTORY - 1957 GOOD CGS HS5120 HISTORY - 1960 GOOD CGS HS5120 HISTORY - 1962 GOOD CGS HS5120 HISTORY - 1963 GOOD CGS HS5120 HISTORY - 1969 GOOD CGS HS5120 HISTORY - 1969 GOOD CGS HS5120 HISTORY - 1971 GOOD NGS HS5120 HISTORY - 1973 GOOD NGS HS5120 HISTORY - 1977 GOOD NGS HS5120 HISTORY - 19880303 GOOD NOS HS5120 HISTORY - 1990 GOOD LOCSUR HS5120 HISTORY - 19920715 GOOD GREENW HS5120 HISTORY - 1997 GOOD USPSQD HS5120 HS5120 STATION DESCRIPTION HS5120 HS5120'DESCRIBED BY COAST AND GEODETIC SURVEY 1852 (RDC) HS5120'THE STATION WAS NOT OCCUPIED. OBSERVATIONS WERE MADE TO THE FLASHING HS5120'RED BEACON LIGHT ABOUT 40 FEET ABOVE THE STATION MARK. HS5120 HS5120 STATION RECOVERY (1935) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1935 HS5120'ABOUT 30 MILES EAST OF BERKELEY AND OAKLAND, ABOUT 15 MILES BY HS5120'ROAD EAST OF WALNUT CREEK, AND ABOUT 15 MILES BY ROAD NORTHEAST HS5120'OF DANVILLE, ON SUMMIT OF MOUNT DIABLO, MOST PROMINENT LANDMARK HS5120'IN VICINITY AND A STATE PARK. AT WEST END OF PARKING SPACE ON HS5120'SUMMIT IS MOUNT DIABLO, AIRWAY LANDMARK BEACON (SEE BELOW). HS5120'AT EAST END OF SUMMIT IS SMALL WOODEN OBSERVATION TOWER BUILT HS5120'OVER ROCK OUTCROP WHICH FORMS HIGHEST PART OF SUMMIT. FROM HS5120'THIS POINT SUMMIT BREAKS OFF STEEPLY IN ALL DIRECTIONS EXCEPT HS5120'WEST. STATION IS UNDER NORTHWEST PART OF THIS PLATFORM, 3 HS5120'FEET NORTHWEST OF CONCRETE PIER WHICH IS AT CENTER OF HS5120'PLATFORM AND AROUND WHICH RANGE FINDERS ARE CENTERED. IN HS5120'1852 STATION WAS MARKED BY HOLE ABOUT 2 INCHES IN DIAMETER HS5120'AND 1-1/2 INCHES DEEP IN CENTER OF BOTTOM OF ANOTHER HOLE 8 HS5120'INCHES IN DIAMETER AND 6 INCHES DEEP. IN 1858 A 1/2-INCH HS5120'HOLE WAS DRILLED IN ROCK. IN 1876 COPPER BOLT WITH CROSSLINES HS5120'ON TOP WAS SET IN SOLID ROCK. OVER THIS WAS PLACED PIER HS5120'WITH 3/4-INCH COPPER BOLT MARKED WITH CROSSLINES CEMENTED HS5120'FLUSH IN TOP. IN 1892 HOLE AT INTERSECTION OF CROSSLINES HS5120'IN UPPER BOLT WAS FOUND ECCENTRIC TO TRUE STATION, AND CENTER HS5120'WAS RE-MARKED WITH NEW CROSSLINES 3/16 INCH SOUTHEAST OF HS5120'HOLE. IN 1922 TOP OF PIER FOUND IN RUINS AND MARK HS5120'RECOVERED DESCRIBED AS 1/2-INCH COPPER BOLT WITH HS5120'CROSSLINES IN TOP SET FIRMLY IN, AND PROJECTING 1/8 INCH HS5120'ABOVE BEDROCK. OLD PIER HAD THREE OPENINGS AT BASE TO PERMIT HS5120'ACCESS TO MARK. PIER WAS REPAIRED, AND ON IT WAS PLACED HS5120'CONCRETE CAP 20 INCHES HIGH, MARKING TOTAL HEIGHT OF PIER ABOUT HS5120'4 FEET. IN CENTER OF CONCRETE CAP WAS HOLE 6 INCHES SQUARE HS5120'TO PERMIT ACCESS TO MARK. IN 1935 REPORTED THAT BRICK AND HS5120'CONCRETE PIER HAD OPENING ON NORTH SIDE TO PERMIT ACCESS TO HS5120'MARK AT GROUND LINE. PIER WAS REPORTED TO EXTEND 3 FEET ABOVE HS5120'OBSERVATION PLATFORM. IN 1876 VERTICAL-ANGLE PIER WAS BUILT HS5120'144.74 FEET WEST OF STATION. BRICK LATITUDE PIER, 27.7 FEET HS5120'SOUTHWEST OF VERTICAL-ANGLE PIER AND 167.82 FEET WEST OF HS5120'STATION. AND TRANSIT-INSTRUMENT PIER, 32.5 FEET SOUTHWEST HS5120'OF VERTICAL-ANGLE PIER. IN 1922 ONLY BASE OF HS5120'VERTICAL-ANGLE PIER WAS FOUND. GRADING OF SUMMIT MAY HAVE HS5120'DESTROYED OTHER OLD AUXILIARY PIERS. IN 1922 REPORTED HS5120'THAT TWO STANDARD REFERENCE DISKS WERE SET IN SOLID HS5120'ROCK, BUT DATA FURNISHED FOR THREE REFERENCE MARKS AS HS5120'FOLLOWS--NO. 1, 2.41 METERS (7.9 FEET) FROM STATION. HS5120'REFERENCE MARK NO. 2, 3.05 METERS (10.0 FEET) FROM HS5120'STATION. REFERENCE MARK NO. 3, 17.14 METERS HS5120'(56.2 FEET) FROM STATION. IN HS5120'1935 NO. 1 WAS RECOVERED IN GOOD CONDITION, REPORTED TO BE HS5120'UNSTAMPED. IN 1931 NO. 2 REPORTED UNDER OBSERVATION HS5120'PLATFORM. NO. 3 NOT RECOVERED IN 1932. MOUNT DIABLO, FLAGPOLE HS5120'(SEE DESCRIPTION THEREOF) IS 14.70 METERS (48.2 FEET) FROM HS5120'STATION. MOUNT DIABLO, AIRWAY LANDMARK HS5120'BEACON (SEE DESCRIPTION THEREOF) IS 65.51 METERS (214.9 FEET) HS5120'FROM STATION. HS5120 HS5120 STATION RECOVERY (1938) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1938 (LAM) HS5120'A COPY OF STANDARD OIL BULLETIN PUBLISHED BY THE STANDARD HS5120'OIL COMPANY OF CALIFORNIA WAS SENT TO THE U.S.C. AND G.S. HS5120'WASHINGTON OFFICE BY LEWIS A. MC ARTHUR, PORTLAND, OREGON. HS5120'THIS BULLETIN CONTAINED A DESCRIPTION OF MOUNT DIABLO AND HS5120'PHOTOGRAPHS WHICH SHOW THE TRIANGULATION STATIONS THEREON, HS5120'MOUNT DIABLO, MOUNT DIABLO, FLAGPOLE, AND MOUNT DIABLO, HS5120'AIRWAY LANDMARK BEACON. HS5120' HS5120'ANOTHER LETTER FROM MR. MC ARTHUR DATED APRIL 20, 1938, IN HS5120'REGARD TO THE INTERSECTION OF THE MOUNT DIABLO MERIDIAN AND HS5120'THE MOUNT DIABLO BASE LINE STATES-- HS5120' HS5120'CAPTAIN LUKENS SAYS THAT CUTTS IN 1852 REPORTED THE ORIGIN HS5120'OF THE LAND SURVEY ON MOUNT DIABLO WAS 3 FEET FROM A COAST HS5120'SURVEY STATION. HE IS OF THE OPINION THAT THE ROCK WHICH HS5120'CONTAINED THE LAND OFFICE POINT HAS BEEN CUT AWAY, AND THAT HS5120'THE POINT IS LOST. HE IS OF THE OPINION THAT IT WAS NOT HS5120'IDENTICAL WITH THE TRIANGULATION STATION. HS5120 HS5120 STATION RECOVERY (1946) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1946 (SPH) HS5120'SINCE THE 1935 RECOVERY OF THIS STATION A LARGE CONCRETE HS5120'BUILDING, WITH OBSERVATION TOWER, HAS BEEN ERECTED OVER IT. HS5120'A FLASHING, RED BEACON LIGHT, ABOUT 40 FEET DIRECTLY ABOVE HS5120'THE STATION MARK, IS ON THE APEX OF THE TOWER. HS5120' HS5120'THE STATION MARK, UNSTAMPED, IS A BRASS BOLT, 1/2 INCH IN HS5120'DIAMETER, PROJECTING 1/2 INCH ABOVE THE BASEMENT FLOOR OF THE HS5120'TOWER, WHICH IS THE SOUTHERN PART OF THE BUILDING. A TAPERED, HS5120'OCTAGONAL, CONCRETE SHAFT, HOLLOW IN THE CENTER, HAS BEEN HS5120'ERECTED OVER THE MARK AND EXTENDS INTO THE SECOND STORY OF HS5120'THE TOWER. TWO OPENINGS, 8 INCHES SQUARE, ARE AT THE BASE HS5120'OF THE SHAFT AND AT THE LEVEL WITH THE MARK. OBSERVATIONS HS5120'MUST BE MADE FROM THE THIRD (TOP) STORY, AND A ROUND OPENING, HS5120'10 INCHES IN DIAMETER, IS IN THE CENTER OF THE FLOOR TO HS5120'ENABLE PLUMBING TO THE MARK. OBSERVATIONS WERE MADE FROM A 4 HS5120'FOOT STAND 7.5 METERS ABOVE THE MARK. HS5120' HS5120'REFERENCE MARK NO. 1, STAMPED MT DIABLO NO 1 1946, IS A HS5120'STANDARD DISK SET IN THE OUTSIDE PART OF THE SOUTH WINDOW SILL. HS5120'IT IS ABOUT 1 METER HIGHER THAN THE FLOOR OF THE OBSERVATION HS5120'ROOM. HS5120' HS5120'REFERENCE MARK NO. 2, STAMPED MT DIABLO NO 2 1946, IS A HS5120'STANDARD DISK SET IN THE OUTSIDE PART OF THE WEST WINDOW SILL. HS5120' HS5120'THE AZIMUTH MARK, STAMPED MT DIABLO 1946, IS A STANDARD DISK HS5120'SET IN A CONCRETE CYLINDER, 11 INCHES IN DIAMETER, PROJECTING HS5120'6 INCHES ABOVE THE SURFACE OF THE GROUND. IT IS SLIGHTLY HS5120'SOUTH OF THE CREST OF THE RIDGE, ABOUT 1/2 MILE SOUTHWEST OF HS5120'THE STATION, 1.6 MILES NORTHEAST BY ROAD FROM THE JUNCTION OF HS5120'THE ROADS FROM DANVILLE AND WALNUT CREEK, AND 0.1 MILE WEST HS5120'OF THE ROAD ENROUTE TO THE SUMMIT. IT IS 16 FEET NORTHWEST HS5120'OF THE THIRD TELEPHONE POLE WEST OF THE ROAD TO THE SUMMIT. HS5120' HS5120'THE STATION CAN BE REACHED BY FOLLOWING ROAD SIGNS FROM THE HS5120'VICINITY OF WALNUT CREEK OR DANVILLE. HS5120 HS5120 STATION RECOVERY (1948) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1948 (CTH) HS5120'THE STATION WAS RECOVERED AS PER THE 1946 DESCRIPTION. ALL HS5120'MARKS WERE IN GOOD CONDITION. HS5120 HS5120 STATION RECOVERY (1951) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1951 (JCE) HS5120'THE 1935 DESCRIPTION OF THE STATION AND MARKS WAS IMPOSSIBLE HS5120'TO CHECK BECAUSE OF EXTENSIVE GRADING AND BUILDING, ON THE HS5120'STATION HILL, SINCE THAT DATE. A NEW DESCRIPTION FOLLOWS-- HS5120' HS5120'THE STATION IS LOCATED ON THE SUMMIT OF MOUNT DIABLE AND HS5120'IN THE BASEMENT OF A LARGE STONE AND CONCRETE BUILDING. THE HS5120'STATION IS OBSERVED FROM THE GLASS INCLOSED LOOKOUT TOWER HS5120'WHICH IS REACHED BY TRAP DOOR FROM THE LOOKOUT PLATFORM ON HS5120'THE ROOF OF THE BUILDING. ON THE SUMMIT OF THE LOOKOUT TOWER HS5120'IS AN AIRWAY BEACON AND FLASHING RED LIGHT. THE STAND MAY HS5120'BE CENTERED BY MEANS OF A PLUMB BOB AND 30 FOOT STRING. A HS5120'KEY TO THE TRAP DOOR MAY BE OBTAINED FROM THE STATE PARK HS5120'HEADQUARTERS ON THE WAY TO THE STATION. A KEY WILL ALSO BE HS5120'NEEDED TO PROVIDE ENTRANCE TO THE BASEMENT AND ACCESS TO THE HS5120'STATION MARK. HS5120' HS5120'THE STATION IS THE CENTER OF A SQUARE HEADED BOLT WHICH IS HS5120'SET INTO A DRILL HOLE IN SOLID ROCK. THIS MARK IS SURROUNDED HS5120'BY A CONCRETE PILLAR WHICH IS ABOUT 8 FEET IN DIAMETER AND HS5120'ABOUT 15 FEET IN HEIGHT. OPENINGS, AT THE BASE OF THE PILLAR, HS5120'PROVIDE A VIEW OF THE STATION MARK. HS5120' HS5120'REFERENCE MARK NUMBER 1 IS A STANDARD DISK, STAMPED MT. DIABLO HS5120'NO 1 1946, SET INTO A DRILL HOLE IN THE STONE SILL OF THE HS5120'LOOKOUT TOWER. HS5120' HS5120'REFERENCE MARK NUMBER 2 IS A STANDARD DISK, STAMPED MT. DIABLO HS5120'NO 2 1946, SET INTO A DRILL HOLE IN THE STONE SILL OF THE HS5120'LOOKOUT TOWER. HS5120' HS5120'NO AZIMUTH MARK WAS SEARCHED FOR OR RECOVERED. HS5120 HS5120 STATION RECOVERY (1957) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1957 (RLE) HS5120'THE STATION MARK, REFERENCE MARKS 1 AND 2 AND THE AZIMUTH HS5120'MARK WERE RECOVERED AS DESCRIBED AND IN GOOD CONDITION. HS5120' HS5120'A LARGE CONCRETE BUILDING WITH A THREE STORY OBSERVATION TOWER HS5120'HAS BEEN ERECTED OVER THE MARK. A FLASHING RED BEACON LIGHT, HS5120'ABOUT 40 FEET DIRECTLY ABOVE THE STATION MARK, IS ON THE APEX HS5120'OF THE TOWER. HS5120' HS5120'THE STATION MARK, UNSTAMPED, IS A BRASS BOLT, 1/2 INCH IN HS5120'DIAMETER, PROJECTING ABOUT 1/2 INCH ABOVE THE BASEMENT FLOOR HS5120'OF THE TOWER, WHICH IS THE SOUTHERN PART OF THE BUILDING. HS5120'A TAPERED, OCTAGONAL, CONCRETE SHAFT, HOLLOW IN THE CENTER, HS5120'HAS BEEN ERECTED OVER THE MARK AND EXTENDS INTO THE SECOND HS5120'STORY OF THE TOWER. TWO OPENINGS, 8 INCHES SQUARE, ARE AT THE HS5120'BASE OF THE SHAFT TO ENABLE PLUMBING OF THE MARK. OBSERVATIONS HS5120'MUST BE MADE FROM THE THIRD (TOP) STORY. A ROUND OPENING, HS5120'10 INCHES IN DIAMETER, IS IN THE CENTER OF THE TOP FLOOR TO HS5120'ENABLE PLUMBING TO THE MARK. OBSERVATIONS WERE MADE FROM A HS5120'4 FOOT STAND ABOUT 7.5 METERS ABOVE THE MARK. HS5120' HS5120'REFERENCE MARK NO 1, A STANDARD DISK STAMPED MT DIABLO NO HS5120'1 1946, IS SET IN A DRILL HOLE IN THE OUTSIDE CONCRETE WINDOW HS5120'SILL. IT IS ABOUT 1 METER HIGHER THAN THE FLOOR OF THE HS5120'OBSERVATION ROOM. HS5120' HS5120'REFERENCE MARK NO 2, A STANDARD DISK STAMPED MT DIABLO NO 2 HS5120'1946, IS SET IN A DRILL HOLE IN THE OUTSIDE CONCRETE WINDOW HS5120'SILL. IT IS ABOUT 1 METER HIGHER THAN THE FLOOR OF THE HS5120'OBSERVATION ROOM. HS5120' HS5120'THE AZIMUTH MARK, A STANDARD DISK STAMPED MT DIABLO 1946, IS HS5120'SET IN THE TOP OF A 12 INCH CONCRETE CYLINDER PROJECTING ABOUT HS5120'6 INCHES ABOVE THE SURFACE OF THE GROUND. IT IS SLIGHTLY SOUTH HS5120'OF THE CREST OF THE RIDGE, 0.1 MILE WEST OF THE BLACKTOP HS5120'ROAD LEADING TO THE STATION AND LOOKOUT TOWER AND 17 FEET HS5120'NORTHWEST OF THE THIRD POWERLINE POLE WEST OF THE BLACKTOP HS5120'ROAD LEADING TO THE STATION. HS5120' HS5120'TO REACH THE STATION FROM THE INTERSECTION OF STATE HIGHWAY HS5120'21 AND DIABLO STREET IN DANVILLE, GO EASTERLY ON DIABLO STREET HS5120'FOR 0.75 MILE TO A FORK AND SIGN MT. DIABLO 14. TAKE THE LEFT HS5120'FORK AND GO 1.1 MILES TO A FORK AND SIGN MT. DIABLO 13. TAKE HS5120'THE RIGHT FORK AND GO 0.6 MILE TO A THREE WAY FORK AND SIGN HS5120'MT. DIABLO 12. TAKE THE CENTER ONE OF THREE FORKS AND GO 8.8 HS5120'MILES TO A POWERLINE, A TRACK ROAD AND THE AZIMUTH MARK 0.1 HS5120'MILE WEST ON THE TRACK ROAD. CONTINUE ON THE BLACKTOP ROAD HS5120'FOR 2.8 MILES TO THE STATION AND LOOKOUT TOWER. HS5120 HS5120 STATION RECOVERY (1960) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1960 (IRR) HS5120'THE STATION MARK, AZIMUTH MARK, AND REFERENCE MARKS NUMBER HS5120'1 AND 2 (SET IN THE CONCRETE WINDOW SILLS OF THE OBSERVATION HS5120'TOWER) WERE RECOVERED IN GOOD CONDITION AND THE 1946, 1951, HS5120'AND 1957 DESCRIPTIONS ARE ADEQUATE. HS5120' HS5120'AN UNSTAMPED REFERENCE MARK DISK ABOUT 48 FEET FROM THE STATION HS5120'IN AZIMUTH ABOUT 78 DEG WAS REMOVED FROM A CONCRETE FLAGPOLE HS5120'BASE PRIOR TO THE REMOVAL OF THE BASE BY THE STATE DIVISION HS5120'OF BEACHES AND PARKS. HS5120 HS5120 STATION RECOVERY (1962) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1962 (IRR) HS5120'THE STATION MARK, AZIMUTH MARK, AND REFERENCE MARKS WERE HS5120'RECOVERED IN GOOD CONDITION AND THE PREVIOUS DESCRIPTIONS HS5120'ARE ADEQUATE. HS5120 HS5120 STATION RECOVERY (1963) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1963 (LGB) HS5120'THE STATION MARK, REFERENCE MARKS 1, 2 AND THE AZIMUTH MARK WERE HS5120'RECOVERED AS DESCRIBED AND FOUND TO BE IN GOOD CONDITION. NO LOCAL HS5120'DISPLACEMENT OF THE MARKS WAS NOTED. THE DISTANCE AND DIRECTION TO HS5120'THE REFERENCE MARKS WERE CHECKED AND FOUND TO BE CORRECT. HS5120' HS5120'THE 1957 DESCRIPTION IS ADEQUATE EXCEPT FOR THE TO REACH. THE HS5120'FOLLOWING IS A NEW TO REACH TO THE STATION. HS5120' HS5120'TO REACH THE STATION FROM THE INTERSECTION OF STATE HIGHWAY 21 AND HS5120'DIABLO STREET IN DANVILLE, GO EASTERLY ON DIABLO STREET FOR 0.75 HS5120'MILE TO A FORK. TAKE LEFT FORK AND CONTINUE EASTERLY FOR 1.1 MILES HS5120'TO A FORK. TAKE RIGHT FORK AND CONTINUE EASTERLY FOR 0.6 MILE TO HS5120'A FORK AT THE ENTRANCE TO MT. DIABLO STATE PARK. TAKE LEFT FORK HS5120'AND GO NORTH AND EAST UPHILL FOR 3.7 MILES TO A LOCKED GATE. (THIS HS5120'GATE IS LOCKED AT 10--00 P.M. IN THE EVENINGS THE KEY CAN BE HS5120'OBTAINED FROM THE MT. DIABLO STATE PARK COMMISSION.) PASS THROUGH HS5120'THE GATE AND CONTINUE NORTH AND EAST UPHILL FOR 4.7 MILES TO A HS5120'POWERLINE, A TRACK ROAD AND THE AZIMUTH MARK 0.1 MILE SOUTH ON HS5120'THE TRACK ROAD. CONTINUE NORTH AND EAST UPHILL FOR 2.8 MILES TO HS5120'STATION AND LOOKOUT TOWER. HS5120' HS5120'THE SAME KEY WILL FIT THE LOCKED DOOR TO GET TO THE STATION MARK HS5120'THAT IS USED TO GET THROUGH THE LOCKED GATE. HS5120' HS5120'OBSERVATIONS MADE FROM A 4 FOOT STAND INSIDE OF THE LOOKOUT TOWER. HS5120 HS5120 STATION RECOVERY (1969) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1969 (WFF) HS5120'THE STATION WAS RECOVERED AS DESCRIBED AND THE DESCRIPTION TO HS5120'REACH THE STATION IS ADEQUATE. HS5120' HS5120'AIRLINE DISTANCE AND DIRECTION FROM NEAREST TOWN HS5120'ABOUT SEVEN MILES NE OF DANVILLE. HS5120 HS5120 STATION RECOVERY (1969) HS5120 HS5120'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1969 (CAA) HS5120'THE STATION MARK, REFERENCE MARKS 1 AND 2 AND THE AZIMUTH MARK HS5120'WERE RECOVERED AND FOUND IN GOOD CONDITION, DUE TO CHANGES IN THE HS5120'ROADS A NEW AND COMPLETE DESCRIPTION FOLLOWS. HS5120' HS5120'TO REACH FROM THE POST OFFICE IN DANVILLE WHICH IS IN THE DANVILLE HS5120'SQUARE SHOPPING CENTER, GO EASTERLY FOR 0.1 MILE TO HARTZ AVENUE, HS5120'TURN RIGHT ON HARTZ AVENUE AND GO SOUTHERLY FOR 0.1 MILE TO THE HS5120'JUNCTION OF DIABLO ROAD, TURN LEFT ON DIABLE ROAD AND GO EASTERLY HS5120'ON DAIBLE ROAD FOR 0.7 MILE TO A FORK (PASSING UNDER INTERSTATE HS5120'HIGHWAY 680). TAKE THE LEFT FORK AS PER SIGN MT DIABLO 14 FOR HS5120'1.7 MILE TO A FORK. TAKE THE RIGHT FORK AS PER SIGN MT DIABLO HS5120'13 FOR 0.9 MILE TO A FORK. TAKE THE LEFT FORK AS PER SIGN MT HS5120'DIABLO 12 FOR 3.85 MILES TO THE ENTRANCE TO THE MT DIABLO HS5120'STATE PARK. CONTINUE FOR 3.1 MILES TO A JUNCTION AND A RANGER HS5120'STATION ON THE LEFT. TURN SHARP RIGHT AS PER SIGN SUMMIT AND HS5120'GO 1.75 MILES TO WHERE THE ROAD MAKES A SHARP CURVE TO THE HS5120'RIGHT, A POWER LINE ON THE LEFT AND A TURN AROUND,(TURN LEFT ON HS5120'THE TURN AROUND AND GO FOR 0.05 MILE TO THE END OF TURN AROUND, HS5120'CONTINUE AHEAD DOWN GRADE FOR 0.1 MILE TO THE AZIMUTH MARK). HS5120'CONTINUE ON MAIN ROAD FOR 2.8 MILES TO THE SUMMIT, ROCK HS5120'LOOKOUT HOUSE AND STATION. HS5120' HS5120'STATION MARK, UNSTAMPED, IS A BRASS BOLT, 1/2 INCH IN DIAMETER, HS5120'PROJECTING ABOUT 1/2 INCH ABOVE THE BASEMENT FLOOR OF THE TOWER, HS5120'WHICH IS THE SOUTHERN PART OF THE BUILDING. A TAPERED, OCTAGONAL, HS5120'CONCRETE SHAFT, HOLLOW IN THE CENTER, HAS BEEN ERECTED OVER THE HS5120'MARK AND EXTENDS INTO THE SECOND STORY OF THE TOWER, TWO HS5120'OPENINGS, 8 INCHES SQUARE, ARE AT THE BASE OF THE SHAFT TO ENABLE HS5120'PLUMBING OF THE MARK. OBSERVATIONS MUST BE MADE FROM THE THIRD HS5120'(TOP) STORY. A 10 INCH OPENING (ROUND) IS IN THE CENTER OF HS5120'THE TOP FLOOR TO ENABLE PLUMBING TO THE MARK. HS5120' HS5120'REFERENCE MARK 1 IS A STANDARD DISK, STAMPED MT DIABLO NO 1 HS5120'1946, IS SET IN A DRILL HOLE IN THE OUTSIDE WINDOW SILL. IT IS HS5120'ABOUT 1 METER HIGHER THAN THE FLOOR OF THE OBSERVATION TOWER. HS5120' HS5120'REFERENCE MARK 2 IS A STANDARD DISK, STAMPED MT DIABLO NO 2 1946, HS5120'IS SET IN A DRILL HOLE IN THE OUTSIDE WINDOW SILL. IT IS ABOUT HS5120'1 METER HIGHER THAN THE FLOOR OF THE OBSERVATION TOWER. HS5120' HS5120'AZIMUTH MARK IS A STANDARD DISK, STAMPED MT DIABLO 1946, IS SET HS5120'IN THE TOP OF A 12 INCH ROUND CONCRETE CYLINDER, PROJECTING ABOUT HS5120'6 INCHES ABOVE THE SURFACE OF THE GROUND. IT IS SLIGHTLY SOUTH HS5120'OF THE CREST OF THE RIDGE, 17 FEET WEST OF A POWER LINE POLE. HS5120' HS5120'REFERENCE MARKS ARE TO CLOSE TO FOCUS ON. HS5120' HS5120'HEIGHT OF LIGHT ABOVE STATION MARK 24.74 FEET. HS5120' HS5120'AIRLINE DISTANCE AND DIRECTION FROM NEAREST TOWN HS5120'8 MILES NORTHEAST OF DANVILLE. HS5120 HS5120 STATION RECOVERY (1971) HS5120 HS5120'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1971 (WMJ) HS5120'THE STATION MARK, REFERENCE MARKS 1 AND 2, AND THE AZIMUTH MARK HS5120'WERE RECOVERED AND FOUND IN GOOD CONDITION. THE DISTANCE HS5120'AND DIRECTION TO THE REFERENCE MARKS COMPARED FAVORABLY WITH HS5120'THE 1935 DATA. DUE TO CHANGES IN THE AREA A COMPLETE NEW HS5120'DESCRIPTION FOLLOWS-- HS5120' HS5120'THE STATION IS LOCATED ABOUT 15 MILES NORTHEAST OF DANVILLE, HS5120'15 MILES EAST OF WALNUT CREEK, ON THE SUMMIT OF MT. DIABLO HS5120'AND IN THE CENTER OF THE FIRST FLOOR OF THE MT. DIABLO LOOKOUT HS5120'TOWER. HS5120' HS5120'TO REACH THE STATION FROM THE INTERSECTION OF HARTZ AVENUE AND HS5120'DIABLO STREET IN DANVILLE GO EASTERLY ON DIABLO STREET FOR HS5120'0.75 MILE TO A FORK AND SIGN, MT DIABLO 14. TAKE THE LEFT HS5120'FORK AND CONTINUE EASTERLY ON DIABLO STREET FOR 1.1 MILES TO HS5120'A FORK AND SIGN, MT DIABLO 14. TAKE THE RIGHT FORK AND GO HS5120'EASTERLY ON DIABLO STREET FOR 0.7 MILE TO A FORK AND SIGN, HS5120'MT DIABLO 12. TAKE THE RIGHT FORK AND CONTINUE EASTERLY ON HS5120'DIABLO STREET FOR 0.95 MILE TO A FORK AND SIGN, DIABLO SCENIC HS5120'BOULEVARD= MT DIABLO 12. TAKE THE LEFT FORK AND CONTINUE HS5120'EASTERLY ON DIABLO SCENIC BOULEVARD FOR 4.0 MILES TO THE HS5120'SOUTH GATE RANGER STATION. CONTINUE UPHILL ON THE SURFACED HS5120'ROAD FOR 3.25 MILES TO RANGER HEADQUARTERS ON THE LEFT. HS5120'TURN SHARP RIGHT AND CONTINUE UPHILL ON THE MAIN ROAD AS PER HS5120'SIGN, SUMMIT 4.5, FOR 1.85 MILES TO A GRAVELED SIDE ROAD HS5120'LEFT. (TO REACH THE AZIMUTH MARK, TURN LEFT AND GO HS5120'SOUTHWEST ON THE GRAVELED ROAD FOR 0.05 MILE TO THE SOUTHWEST END HS5120'OF A PARKING AREA. CONTINUE SOUTHWEST ON A TRACK ROAD FOR HS5120'0.05 MILE TO A POWER POLE AND THE MARK.) CONTINUE UPHILL ON HS5120'THE MAIN ROAD FOR 3.0 MILES TO THE SUMMIT OF THE MOUNTAIN, A HS5120'LOOKOUT TOWER AND THE MARK AS DESCRIBED. HS5120' HS5120'THE STATION MARK IS A 1/2-INCH IN DIAMETER BRASS BOLT THAT HS5120'PROJECTS 1/2-INCH ABOVE THE GROUND FLOOR OF THE LOOKOUT TOWER. HS5120'A TAPERED, OCTANGONAL, CONCRETE SHAFT WITH AN 8-INCH OPENING HS5120'IN THE CENTER HAS BEEN ERECTED OVER THE MARK. TWO OPENINGS HS5120'IN THE BASE OF THE SHAFT ENABLE PLUMING OF THE MARK. HS5120'OBSERVATIONS MUST BE MADE FROM THE THIRD STORY OF THE TOWER. A HS5120'10-INCH HOLE IN THE FLOOR ENABLES THE PLUMING OF THE HS5120'MARK. HS5120' HS5120'REFERENCE MARK 1 IS A STANDARD DISK STAMPED MT DIABLO NO 1 HS5120'1946, CEMENTED IN A DRILL HOLE IN THE OUTSIDE CONCRETE WINDOW HS5120'SILL OF THE BUILDING. IT IS ON THE SOUTHEAST SIDE OF THE HS5120'BUILDING AND ABOUT 3 FEET ABOVE THE OBSERVATION ROOM FLOOR. HS5120' HS5120'REFERENCE MARK 2 IS A STANDARD DISK STAMPED MT DIABLO NO 2 HS5120'1946, CEMENTED IN A DRILL HOLE IN THE OUTSIDE CONCRETE WINDOW HS5120'SILL OF THE BUILDING. IT IS ON THE WEST SIDE OF THE BUILDING HS5120'AND ABOUT 3 FEET ABOVE THE OBSERVATION ROOM FLOOR. HS5120' HS5120'THE AZIMUTH MARK IS A STANDARD DISK STAMPED MT DIABLO 1946, HS5120'SET IN THE TOP OF A ROUND CONCRETE MONUMENT THAT IS 12-INCHES HS5120'IN DIAMETER AND PROJECTS 6 INCHES ABOVE THE GROUND SURFACE. HS5120'IT IS 17 FEET NORTHWEST OF THE THIRD POWER LINE POLE WEST OF HS5120'THE SURFACED ROAD. HS5120' HS5120'AIRLINE DISTANCE AND DIRECTION FROM NEAREST TOWN--15 MILES HS5120'NORTHEAST OF DANVILLE HS5120 HS5120 STATION RECOVERY (1973) HS5120 HS5120'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1973 (CLN) HS5120'THE STATION MARK, AZIMUTH MARK, AND REFERENCE MARKS 1 AND 2 HS5120'WERE RECOVERED IN GOOD CONDITION AND THE PREVIOUS DESCRIPTIONS HS5120'ARE ADEQUATE. HS5120' HS5120'AIRLINE DISTANCE AND DIRECTION FROM NEAREST TOWN--6 MILES HS5120'NORTHEAST OF DANVILLE HS5120 HS5120 STATION RECOVERY (1977) HS5120 HS5120'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1977 (CA) HS5120'THE STATION WAS RECOVERED IN GOOD CONDITION AS PREVIOUSLY HS5120'DESCRIBED. THE 1946, 1951, AND 1957 DESCRIPTIONS ARE HS5120'ADEQUATE. THE REFERENCE MARKS WERE NOT SEARCHED FOR. HS5120 HS5120 STATION RECOVERY (1988) HS5120 HS5120'RECOVERY NOTE BY NATIONAL OCEAN SERVICE 1988 (FRD) HS5120'THE STATION WAS RECOVERED AT THIS DATE. REFERENCE MARKS 1 AND 2 WERE HS5120'RECOVERED IN GOOD CONDITION. THE 1971 DESCRIPTION IS ADEQUATE EXCEPT HS5120'THAT OBSERVATIONS ARE NOT POSSIBLE FROM THE THIRD STORY WHICH IS NOW A HS5120'RADIO ROOM. A MONUMENT HAS BEEN ERECTED ON THE SECOND FLOOR WHICH HS5120'PREVENTS PLUMBING THE MARK FROM ABOVE.$DESCRIBED BY T.K. PORTA HS5120 HS5120 STATION RECOVERY (1990) HS5120 HS5120'RECOVERY NOTE BY LOCAL SURVEYOR (INDIVIDUAL OR FIRM) 1990 (BRH) HS5120'THE STATION WAS RECOVERED IN GOOD CONDITION AS DESCRIBED. HS5120 HS5120 STATION RECOVERY (1992) HS5120 HS5120'RECOVERY NOTE BY RONALD GREENWELL 1992 HS5120'THE STATION WAS RECOVERED IN GOOD CONDITION AS DESCRIBED. HS5120 HS5120 STATION RECOVERY (1997) HS5120 HS5120'RECOVERY NOTE BY US POWER SQUADRON 1997 HS5120'RECOVERED IN GOOD CONDITION.