Another indication of how shallow the seas were in the Middle Jurassic of southern Israel. This bedding plane in the Matmor Formation of Makhtesh Gadol has a gastropod (snail) fossil in the center of the image surrounded by angular shells of fossil mytilids (clams commonly called mussels today). In life the mytilids had attached to the gastropod and each other by fine yet strong byssal thread produced by a special gland. This kind of relationship is very common in tidal pools and other shallow areas where wave action is strong.
