Coral patch reefs in the Bajocian (Middle Jurassic) of Lorraine

Summary An account is given of coral patch reefs in the Bajocian of Lorraine, France, and a distinctive ecological association in the other invertebrate fauna recognized, which compares closely with that present in the late Oxfordian reef facies of southern England. The inference is made of a series of low mounds on the original sea bed, composed of coralline sheet structures interfingering with calcareous sediment which locally and periodically enveloped the coral colonies. Compared with Recent patch reefs in the Bahamas and around Bermuda, important differences can be inferred for the Jurassic structures, principally the lack of significant topographic relief, major internal cavities, erosion and algal incrustation.