18 Mr. J. Lycett on the Fossils 



which immediately underlie the Bradford clay, we And an alternating series 

 of limestones and clays or marls, extremely variable both in thickness and 

 extent. Certain of these bands, and more especially one of a compact 

 cream-coloured limestone, are eminently shelly, but will seldom allow of 

 the shells being separated entire. These gradually pass downwards into 

 the middle subdivision, where the rock is more barren of organic remains, 

 and sandy. 



The lower subdivision assumes a very different aspect ; we here find 35 

 or 40 feet of shelly beds, separating into large masses, and well-suited for 

 the mason. From the third or lower subdivision it is that nearly the whole 

 of our fossils are derived, the stone usually admitting their being cleaved 

 with a knife. 



The uppermost portion of this series, the planking*, which is from 8 to 

 10 feet thick, contains the most numerous suite of zoophagous Trachelipods, 

 several of which are not found beneath it. To this succeeds a few feet of 

 incoherent sandy rock, the upper part of which is nearly destitute of shells, 

 or only occupied by a few species of small bivalves. The shells gradually 

 increase in number downwards, and repose on several beds of hard shelly 

 rock, locally called Weatherstone. Here more especially abound the valves 

 of small oysters, which at length constitute no inconsiderable portion of 

 the mass, and whose peculiar structure imparts such great hardness to the 

 deposit, that the lower few inches strike fire with the tools of the workmen. 

 These shelly beds or weatherstones have a high character for durability ; 

 they have a coarse aspect ; when once dried by exposure to the sun they 

 do not readily absorb water, and consequently resist the action of frost ; a 

 careful selection is however necessary to ensure this desideratum. The 

 south transept of Minchinhampton church, five centuries old, is built of this 

 stone, and notwithstanding its very exposed situation, displays all the 

 sharpness and distinctness in its angles and carving which we should expect 

 in a modern edifice. 



The Fuller's earth which underlies these deposits is but partially and 

 imperfectly exposed within the district ; it consists of a series of brown and 

 blue marls and clays traversed by three or four bands of a hard argillaceous 

 rock locally called clay rag. Some portions of the clays, and more especially 

 the rag-stones, are made up of the valves of small oysters, chiefly Ostrea 

 acuminata ; the organic remains, however, are far from numerous, when 

 counted by number of species ; they are nearly all bivalves, and I have not 

 observed any which are not likewise found in the weatherstones above. 

 The Fuller's earth constitutes the most fertile soil in this part of the county j 

 when properly drained it is well-adapted for pasturage and orchards, which 

 together with a good supply of water derived from the superincumbent 

 Oolite, has made it in populous districts the chosen seat of man's habitation ; 

 accordingly its course may be traced by a belt or terrace, more or less wide, 

 of houses and gardens encircling the hill-sides. Landslips from such a 

 yielding deposit, as might be expected, are frequent, and thereby render the 

 barren slope of the Inferior Oolite fertile : a coating of its marls sometimes 

 extends even down to the lias. The numerical proportion of species obtained 

 by me from the Minchinhampton Great Oolite are in number as follows :— 

 Bivalves, 164, Univalves, 141, Radiara, 13, Cephalopoda, 9. Of the 

 latter are Ammonites j these are so scarce, that 50 specimens probably 

 exceed the entire number. Of Nautili there are two species, one of which 

 has furnished only three specimens, and the other is far from numerous. 

 The Belemnites have only one species, small and likewise scarce. 



Of the 141 Univalves 45 pertain to carnivorous genera, exclusive of 8 

 species of Phasianella, the living shells of which are now known to be both 

 carnivorous and phytophagous. These genera are, Ncrinaa 13 species, 

 Cerithium 5, Murex 6, Buccinum 2 ; a new group of large shells belong- 

 ing to the Muricidce, to which as yet no generic appellation has been given, 



• A local term indicating a thin-b»dded stone. 



