U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                   PUBLICATION DATE:  11/21/1991
Station ID: 8512451                                SUPERCEDED DATE:   04/21/2003
Name:       PONQUOGUE POINT, SHINNECOCK BAY                   
            NEW YORK
NOAA Chart: 12353                                  Latitude:         40° 51.0' N
USGS Quad:  QUOGUE                                 Longitude:        72° 30.2' W


To reach the tidal bench marks from the intersection of State Highway 27 and
Ponquogue Avenue in Hampton Bays, proceed south on Ponquogue Avenue for 1.5
miles (2.4 km), then east on Shinnecock Road for 0.5 mile (0.8 km), then south
on Foster Avenue for 0.5 mile (0.8 km) to the U.S. Coast Guard Station
Shinnecock near the north end of Ponquogue Bridge.  The bench marks are near the
station and along Ponquogue Avenue.  The tide gage and staff were near the south
end of the Coast Guard boat basin bulkhead.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  2451 A 1989

MONUMENTATION:           Survey Disk                               VM#:     7439
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Base


The primary bench mark is set flush in the SE corner of the 4x4-foot (1x1 m)
concrete base of the Coast Guard station  flagpole, 124.3 feet (37.9 m) north of
hte NW corner of the administration building, 123.2 feet (37.6 m) WSW of the
bulkhead, and 31.7 feet (9.7 m) ENE of the east edge of the westernmost parking
area.



                         BENCH MARK STAMPING:  NO 3 1933 RESET 1943

MONUMENTATION:           Survey Disk                               VM#:     7436
AGENCY:                                                            PID#:  KU0419
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in a concrete monument along the old Ponquogue Bridge Road
which runs just east of the present highway, on the inside of a curve, 80.8 feet
(24.6 m) SSE of power pole #26, 16.2 feet (4.9 m) west of the centerline of the
road, 9.9 feet    (3.0 m) north of power pole #27, 1.4 feet (0.4 m) west of the
east edge of the concrete sidewalk, and 0.3 foot (0.1 m) below the surface of
the sidewalk.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                   PUBLICATION DATE:  11/21/1991
Station ID: 8512451                                SUPERCEDED DATE:   04/21/2003
Name:       PONQUOGUE POINT, SHINNECOCK BAY                   
            NEW YORK
NOAA Chart: 12353                                  Latitude:         40° 51.0' N
USGS Quad:  QUOGUE                                 Longitude:        72° 30.2' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  W 320 1943

MONUMENTATION:           Survey Disk                               VM#:     7437
AGENCY:                                                            PID#:  KU0415
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in a concrete monument in the NE quarter of the
intersection of Ponquogue and Bay Avenues, 1.4 miles (2.3 km) SE along Ponquogue
Avenue from the Post Office at Hampton Bays, 58 feet (18 m) north of the
centerline of Bay Avenue, 33 feet (10 m) east of the centerline of Ponquogue
Avenue, 11 feet (3 m) SE of NYT power pole #16 S, and 0.3 foot (0.1 m) above
ground level.



                         BENCH MARK STAMPING:  PONQ NO 1 1965

MONUMENTATION:           Survey Disk                               VM#:     7438
AGENCY:                                                            PID#:  AE4707
SETTING CLASSIFICATION:  Concrete Deck


The bench mark is set flush in the concrete deck of the Coast Guard boat basin
dock, 140.7 feet (42.9 m) south of the SE corner of the administration building,
26.2 feet (8.0 m) NW of the SE corner of the dock, and 1.9 feet (0.6 m) ESE of
the west edge of the concrete deck.



                         BENCH MARK STAMPING:  2451 B 1989

MONUMENTATION:           Survey Disk                               VM#:     7440
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Foundation


The bench mark is set flush in the concrete foundation of the Coast Guard boat
house, 60.9 feet (18.6 m) SSW of the bulkhead, 18.8 feet (5.7 m) ESE of the NW
corner of the building, and o.7 foot (0.2 m) ESE of the NW edge of the
westernmost garage-type door along the north side of the building.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                   PUBLICATION DATE:  11/21/1991
Station ID: 8512451                                SUPERCEDED DATE:   04/21/2003
Name:       PONQUOGUE POINT, SHINNECOCK BAY                   
            NEW YORK
NOAA Chart: 12353                                  Latitude:         40° 51.0' N
USGS Quad:  QUOGUE                                 Longitude:        72° 30.2' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  2451 C 1989

MONUMENTATION:           Survey Disk                               VM#:     7441
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Footing


The bench mark is set flush in the SW corner of the south concrete footing of
the Coast Guard antenna tower, 63.0 feet (19.2 m) WNW of the SW corner of the
foundation of a small brick shed, 26.7 feet (8.1 m) SSW of the face of a
concrete fence post along the north border of the Coast Guard grounds, 12.1 feet
(3.7 m) east of the east corner of a chain link fence surrounding the tower, and
0.3 foot (0.1 m) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                   PUBLICATION DATE:  11/21/1991
Station ID: 8512451                                SUPERCEDED DATE:   04/21/2003
Name:       PONQUOGUE POINT, SHINNECOCK BAY                   
            NEW YORK
NOAA Chart: 12353                                  Latitude:         40° 51.0' N
USGS Quad:  QUOGUE                                 Longitude:        72° 30.2' W


                            T I D A L   D A T U M S 


Tidal datums at PONQUOGUE POINT, SHINNECOCK BAY based on:

     LENGTH OF SERIES:      12 MONTHS
     TIME PERIOD:           JULY 1989-JUNE1990
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8461490 NEW LONDON


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:

     HIGHEST OBSERVED WATER LEVEL (10/19/1989)    =   4.91
     MEAN HIGHER HIGH WATER (MHHW)                =   3.20
     MEAN HIGH WATER (MHW)                        =   2.94
     MEAN TIDE LEVEL (MTL)                        =   1.53
   * NATIONAL GEODETIC VERTICAL DATUM-1929 (NGVD) =   1.04
     MEAN LOW WATER (MLW)                         =   0.13
     MEAN LOWER LOW WATER (MLLW)                  =   0.00
     LOWEST  OBSERVED WATER LEVEL (11/12/1990)    =  -1.56

   * NGVD reference based on elevations published in Quad 400724, 1968, and NOS
     leveling of 1990. 
National Geodetic Vertical Datum (NGVD 29)

Bench Mark Elevation Information           In FEET above:

     Stamping or Designation               MLLW        MHW

     2451 A 1989                            9.75      6.81
     NO 3 1933 RESET 1943                   5.68      2.74
     W 320 1943                            24.07     21.13
     PONQ NO 1 1965                         7.48      4.54
     2451 B 1989                            8.36      5.42
     2451 C 1989                            9.34      6.40


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  5

                                                   PUBLICATION DATE:  11/21/1991
Station ID: 8512451                                SUPERCEDED DATE:   04/21/2003
Name:       PONQUOGUE POINT, SHINNECOCK BAY                   
            NEW YORK
NOAA Chart: 12353                                  Latitude:         40° 51.0' N
USGS Quad:  QUOGUE                                 Longitude:        72° 30.2' W


                             D E F I N I T I O N S


Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch.  It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD 88).

NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded.  NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads.  NGVD 29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929.  Bench mark elevations relative to NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at 
National Geodetic Survey.

NAVD 88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint.  NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights.  Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at 
National Geodetic Survey.

NGVD 29 and NAVD 88 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.

The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed.

The NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum.  As a result of
this averaging, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.