Paul, "slime" is probably a loose translation of a French word meaning "thin mud or slime". I read it as a euphemism for feces and pseudofeces. Pseudofeces consist of the material that oysters and some other sessile animals accumulate in their gills and then expel in a mucous packet; it is not digested material. Most marine sediment (and terrestrial soil, for that matter) has passed repeatedly through the guts of worms and other organisms. For instance, the tiny rods of clay often found in windrows on Gulf of Mexico beaches are the feces of ghost shrimp (Callianassa and relatives), which live in deep burrows just offshore. The shrimp are both numerous and active, and accumulations of clay consisting of shrimp feces can be several centimeters (inches) thick, e.g., on the Georgia coast. The accumulations of oyster feces and pseudofeces near oyster beds can be awesomely thick (feet/meters) in Gulf estuaries. So, no, I don't find the French Crepidula problem to be unbelievable in this aspect. I agree that the D-Day part is unbelievable; this part has the hallmarks of an "urban legend" (something that people like to hear and will, unfortunately, remember clearly when everything else has faded). Andrew K. Rindsberg Geological Survey of Alabama