- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
Fresh information on the ecology, sedimentology and structure of the lower Silurian (Llandovery) purple shale of Shropshire has emerged as a result of large-scale excavations. The griestoniensis zone is proved, and correlated by shelly fossils with the C 5 substage of the type Llandovery area. Current directions indicate a source area up-slope to the south-east. Most of the fauna constitutes a Clorinda community, but towards the top of the sequence a Clorinda/Stricklandia mixture is developed.