Location and geological setting
The Granton Shrimp Bed is located on the south shore of the Firth of Forth about 3 km (2 mi) from the centre of Edinburgh. It consists of a layer of dolomitic limestone surrounded by Dinantian mud shales which were formed as a result of the deposit of material in either a delta plain setting or in an inter-distributary bay, where sedimentation occurred because of flood-generated incursions.
The shrimp bed resulted from the periodic inundations of marine water into stagnant lagoons, each incursion leaving a lamina of limestone rich in the fossils of soft-bodied marine invertebrates and other animals. These conditions of fluctuating salinity seem to have created a suitable habitat for an assemblage of shrimp-like crustaceans, fish, bellerophonts, conchostracans and ostracods. The sudden changes in salinity caused mass mortalities of this fauna, and also brought marine species such as orthocone cephalopods, polychaete worms and conodonts, which are also found fossilised here.