TIDAL DATUM PLANES 61 
Since the rise along the Gulf coast is at different rates, the most plausible expla- 
nation is an assumption of local coastal movement. Apparently the coast in the vicinity 
of Galveston is subsiding at a more rapid rate than the coast to the eastward. 
Pacific Coast.—Figure 32 gives the yearly values of sea level at four stations on 
the Pacific coast of continental United States. In general the changes from year to 
year at the stations are less than a tenth of a foot, although occasionally they may be 
as much as two- or three-tenths of a foot. In general, too, the variations are in the same 
direction at all four stations; when sea level is high (or low) at one station it is also high 
(or low) at the other stations. 
1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 
San Diego e : 
FIG. 32.—Yearly sea level, Pacific coast. 
