Geological Society. 301 



author, are Clypeus sinuatus, Terebratula Jimbriata, Modiola plicata, 

 Pholadomija fidicula, Trigonia costata, Gryphcea columba (Sowerby), 

 Lima proboscidea, and Ammonites corrugatus. 



The formation occupies, in Gloucestershire, a much greater super- 

 ficial importance than has been hitherto assigned to it. Besides form- 

 ing the upper part of the escarpment, it constitutes, to the south of 

 Cheltenham, the inclined plane which ranges between the crest of the 

 hills and the ridge of Fuller's earth and great oolite, and, to the north 

 of that town, the summit of the whole of the hills, with the exception 

 of an occasional capping of great oolite. 



Fuller's earth. — This argillaceous deposit is of much less importance 

 in the district surveyed than in. the neighbourhood of Bath. The 

 mineral to which it owes its designation is wanting, or is represented 

 by only an occasional bed of impure, useless Fuller's earth. Its greatest 

 thickness in Gloucestershire is estimated not to exceed fifty feet : in 

 the Cotteswolds it was found to be not more than twenty-five j and 

 the deposit was ascertained to thin out to the north-east of a line 

 passing from the neighbourhood of Winchcomb to Burford. 



Great oolite. — The threefold arrangement of upper rags, fine free- 

 stone, and lower rags, into which this formation was divided near 

 Bath, does not prevail through the whole of the district examined. 

 The upper rags, consisting of soft freestone and hard shelly oolite, 

 were traced to Cirencester ; but to the north-east of that town they 

 are replaced by a rubbly white argillaceous limestone. In the middle 

 division, fine workable freestone is of partial occurrence ; and the 

 greater number of the beds are composed of hard oolitic limestone. 

 The lower rags, consisting of coarse shelly oolites, resting upon 

 closely-grained or crystalline limestone, extend from Bath to Wotton 

 Underedge ; but in the neighbourhood of that town a change occurs, 

 and their position is occupied by beds of fissile calcareous limestone. 

 These strata were traced through the whole of the north-east of Glou- 

 cestershire, and to the neighbourhood of Burford. They are exten- 

 sively worked as a tile-stone j possess the lithological character of 

 the Stonesfield slate ; have their fissile property developed by exposure 

 to atmospheric agency j contain Trigonia impressa, the characteristic 

 fossil of Stonesfield ; and, on comparing the strata of Burford with 

 those which rest at Stonesfield on the slaty beds, it was found that 

 an almost perfect identity of character and order of position prevailed 

 at the two localities. The following table contains Dr. Fitton's accu- 

 rate enumeration of the beds of Stonesfield (see Zoological Journal, 

 vol. iii.), and a list of those wrought at the Windrush quarries near 

 Burford. 



Burford. 



Top. Rubbly limestone 1 foot. 



Brownish marlstone ... 6 feet. 



Rubbly limestone 4 feet. 



Pale sandy marl 3 feet. 



Rubbly marlstone \ foot. 



Light-coloured clay ... £ foot. 

 Rag and freestone 15 feet. 



Sandy laminated grit. 



Stonesfield. 

 Top. Rubbly limestone. 

 Clay. 



Limestone. 

 Blue clay. 

 Oolite. 

 Blue clay. 

 Rag, oolitic limestone. 



Sandy bed, containing the slate. 



