Oops! In my last post, the line:
Bivalves which live in shallow water, in climates which fluctuate
between frigid and warm, may have true annular growth rings . . .
should have read:
Bivalves which live in shallow water, in climates which fluctuate
between frigid and warm, may have true ANNUAL growth rings . . .
All growth rings are annular (ring-shaped), but not all are annual (yearly).
Paul M.