Bradford Clay

Bradford Clay, a subdivision of the Great Oolite (Lower Oolite), is a blue unctuous clay, occurring at Bradford, near Bath, and extending for a few miles around: it is about 10 feet thick at Bradford, but may be thicker at Farleigh. It is remarkable for the occurrence in it of large numbers of a Crinoid (q.v.), Apicrinites Parkinsoni. The upper surface of the calcareous rock on which the clay rests is completely incrustated over with a continuous pavement formed of the stony bases of this crinoid. It had once formed the bottom of a sea, in which these animals lived, their stems bending with every motion of the water, and their star-like crown of arms outstretched in search of food. At length, however, the clear water was invaded by a current largely charged with mud, which threw them down, and broke most of their stems off near the base. The stem, body, and arms have been dismembered, and are confusedly scattered through the clay. Although Bradford Clay is considered a local deposit, yet deposits containing the same fossils occur in Dorsetshire.