Bradford Clay

Bradford Clay, a local deposit of pale-grey calcareous clay, with seams of tough brown limestone and calcareous sandstone, occurring at various horizons near the upper part of the Bathonian or Great Oolite, and named from its occurrence at Bradford-on-Avon, Wiltshire. It is generally below the Forest Marble, and corresponds, no doubt, in part to the Blisworth or Great Oolite Clay of Northamptonshire. Its greatest thickness seems to be near Farleigh, where it is between 40 and 60 feet. Its most characteristic fossils are Waldheimia digona and Apiocrinus rotundus (or Parkinsoni). The latter is known as the Bradford or Pear Encrinite, its "calyx" or body much resembling a pear, whilst single joints of the stem are called "coach-wheels." In Wiltshire numbers of these encrinites may be seen attached to the upper surface of the underlying limestone where they lived until overwhelmed by the clayey sediment in which their remains are now imbedded.