South-western Coal District of England. 301 



which belong to the inferior oolite. The subjacent black shale attains occa- 

 sionally a thickness of from 15 to 20 feet, and contains thin beds of a greenish 

 siliceous grit, highly charged with mica, and loaded with the scales, teeth, 

 palates and bones of fishes, and the bones of many gigantic reptiles. These 

 siliceous strata, from the abundance of their organic remains, are known by 

 the name of "the Bone-beds:" they abound in iron-pyrites, and in rolled 

 fragments of bone and of differently-coloured clay-stone, of which the darker 

 varieties resemble the bone in colour. They probably form an under-bed, 

 coextensive with the lias throughout its whole course in the estuary of the 

 Severn, being found at a spot * on the right bank of that river 7 miles above 

 Gloucester, at the cliff of Westbury a little below Framilode passage, and 

 at the Old Passage in the opposite cliffs of Aust and Annards, in which and 

 in the cliff of Westbury their structure is best displayed. On the right bank 

 they are seen in Monmouthshire at Gold-cliff, and in Glamorganshire at the 

 village of St. Hilary, near Cowbridge; on the left bank on the coast of 

 Somersetshire, at the western extremity of Clevehill, near the town of 

 Watchet f . They are also found at some distance from the Severn, on the 



* Mr. Halifax has here procured a black solid bone, larger than the humerus of a horse, be- 

 longing to some gigantic reptile. 



f This discovery of the bone-bed near Watchet has been made by Robert Anstice, Esq. of 

 Bridgewater. It there forms a stratum from 2 to 9 inches thick, chiefly composed of white 

 quartzose sand, with small pebbles of quartz and a little mica sparingly interspersed, the whole 

 being cemented together by carbonate of lime. The cement occasionally assumes the character 

 of lias, and forms septaria in the bed of sandy breccia. It then is often full of small bivalve 

 shells. The whole abounds with animal remains, which are often inseparably attached to one 

 another by iron-pyrites. The bones are in few cases unbroken, and in one case only has Mr. A. 

 found teeth or palatal bones attached to a jaw or palate, although they all occur abundantly 

 throughout the stratum in a detached state. They are of a jet black colour, and have a highly 

 polished surface ; but, from the brittleness of their substance and the hardness of the matrix, it 

 is difficult to disengage without destroying them. Only a few fragments of large bones have 

 been found ; the rest seem generally to have belonged to small animals. The remains are as 

 follows. 



1. Fragments of spines of the same nature as those represented in plate iv. fig. 1. 2 and 3. 

 vol. i. 2nd series, Geol. Trans. They belong to two varieties; both of which differ in some 

 points from that in the plate referred io^ and approach nearer to that described in Walcot's ac- 

 count of the petrifactions near Bath. One of them is less deeply furrowed than that in the 

 figure; the other is scarcely furrowed at all, and has tubercles on the sides towards the point. 

 In neither of them are the dentiform processes so abundant, or so regularly disposed, as iu 

 the figure. 



2. Many varieties of palates and teeth, some of the latter resembling those represented in 

 fig. 5 to 10 of the plate above referred to. 



3. Scales of several varieties of fish, many of them corresponding exactly with those of the 



