CONTENTS 

 FIGURES-Continued 



Page 



11 Illustration of tidal datums (Los Angeles, California (Outer Harbor), January 



1973 37 



12 Relationship between NGVD and several tidal datums between Montauk and 



The Battery 38 



13 Location of tide stations used in establishing the National Geodetic Vertical 



Datum (NGVD) of 1929 39 



14 First-order level net (1963) showing MSL variations 42 



15a Sample NOS index map of tidal bench-mark locations 43 



15b Sample of related NOS index map numbers 44 



16 Sample NOS sheet of description of tidal bench marks 45 



17 Location of reference and comparative tide stations, Atlantic, gulf, and Pacific 



coasts 48 



18 Areal extent of tidal types and locations of stations with illustrated tidal curves . 49 



19 Schematic illustration of apparent gravity 51 



20 Equipotential or "level" surfaces 51 



21 Variation in annual MSL at New York, New York (The Battery) ; Portland, 



Maine; Baltimore, Maryland; and Charleston, Soutli Carolina 55 



22 Variation in annual MSL at Charleston, South Carolina; Mayport, Miami Beach, 



and Cedar Key, Florida 55 



23 Variation in annual MSL at Cedar Key £md Pensacola, Florida; Eugene Island, 



Louisiana; and Galveston, Texas 56 



24 Variation in annual MSL at Seattle, Washington; San Fr£mcisco and San Diego, 



California; and Honolulu, Hawaii 56 



25 Variation in annual MSL at Ketchikan and Skagway, Alaska 57 



7 



