I'm Fitz Fitzgerald, filling in for the sheriff.
The result is that the tracery itself has to support the structure above it - is, in fact, constructional - whereas in most other countries the tracery is merely, as it were, a pierced screen filling in a constructional arch.
These are simply parts of the sea which have escaped the filling-in process carried on by the great river and the lesser streams. A second class, called " ox-bow" lakes, large in numbers but small in area, includes ordinary cut-off meanders along the Mississippi and Red rivers.
The shore-line is irregular, and has been modified by the construction of sea-walls and the filling in of shallow bays.