XL STONESFIELD BEDS. 147 



UPPER DIVISION, composed of clays and shelly limestones, more 



or less oolitic, to which the names of Cornbrash, Forest marble, 



and Bradford clay were applied by Smith. 

 MIDDLE DIVISION, composed of compact shelly or oolitic limestone, 



in beds of various thickness, with marly or argillaceous 



partings. 

 LOWER DIVISION. Thin-bedded limestones associated with sands, 



1 Stonesfield slate,' or laminated 'ragstone.' 



THE LOWER DIVISION OF THE GREAT OOLITE. 



' The Stonesfield Beds.' 



This range of variable strata, oolitic, arenaceous, and ferruginous, 

 corresponds to the ' lower rags/ a rather indistinct part of the great 

 oolitic system in the south-west of England ; it becomes conspicuous 

 near Wotton-under-Edge, passes across the Cotswold Hills, and 

 traverses Gloucestershire and Oxfordshire. 



High in the hills near Wotton-under-Edge it is plainly to be 

 recognized as a laminated rock, lying over the thick marly strata, 

 which are the ' fullers-earth and fuller's -earth rock' of W. Smith. 

 False-bedding is very common in this rock over extensive tracts, 

 a mark of currents in shallow water. It is often sandy and cal- 

 careous; fissile by art, and by exposure to atmospheric agencies. 

 It contains Trigonia impressa, but is not rich in fossils till we reach 

 the country between Cheltenham and Burford. 



In this line at Sevenhampton, near Cheltenham, and Eyeford, 

 near Stow, are many extensive quarries where this stone is dug for 

 roofing, and is called ' slate. 1 The succession of strata in general 

 terms may be thus expressed ! : the lower portions, a and b, being 

 regarded as ' Stonesfield beds, 1 and c as parting them from the ordi- 

 nary Great oolite : 



ft. in. 

 f Shelly clay Rhynchonellse . . . . . . .60 



I Thin layers of shelly oolite 08 



(In these upper strata Ostrea acuminata occurs.) 



Sandy marl and a few shells (sometimes absent) . . . 8 o 

 b Ragstone, a hard oolite, in thin beds, with blue centres shells, 



plants, fish-teeth, one ammonite . . . . . 14 o 

 a Slate, sandy, laminated, with few shells, one ammonite . . 4 

 (Clay appears beneath.) 



1 Brodie on Fossil Insects, p. 41. ^ 

 L 3 



