Fossil poop of this type attributed to animal without a spinal column that lived predominantly in salt water. This could include, but is not limited to, mollusks, crustaceans, echinoderms, etc. Lobster Logs?(Pyritized Invertebrate Coprolite Pellets) Chamber Pot(Invertebrate Coprolite Pellets in Matrix) Worms Crawl In, Poop Comes Out(Crab carapace with segmented worm coprolites) (Chamber Pot!)