=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991
St Marks            940/047 RLR(1967) is 8.1m below BM6
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 12-Jul-1993
St Marks            940/047 RLR(1967) is 8.1m below BM6
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 29-Jul-1993
Many stations on the Gulf coast have large values for September 1961.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 09-Feb-2012
St. Marks is now an Historic Station. Last data received was that for 1975.
Although there are entries for both St. Marks Lighthouse and St. Marks City and
the latter does list an earlier benchmark 6 the reference to this and the TGZ
does not tally with the value from the original RLR diagram.