460 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 19, 



considered as Kimmeridge ; and tlie only way in whicli we could 

 construct a section which, should show the relations of the seyeral 

 groups up to the chalk, was by supposing that a fault existed at the 

 base of that escarpment by which the Kimmeridge clay and gault 

 were brought to the same level. The solution of this was one of the 

 points we proposed for our second day's work. To enable us to em- 

 brace a larger area, our party separated ; Prof. Forbes, Mr. Prest- 

 wich, and Mr. Tylor to examine some reputed quarries of Portland 

 stone near Stamford, and then to make a transverse section to the 

 chalk ; Mr. Sharpe and Mr. Austen to take up the section from 

 Fernham, and carry it on to the escarpment of the WTiite Horse. 



Quitting the horizontal platform of coral rag by Bowling Green 

 Farm, we struck across the grass-lands by AYichwood and Little 

 Medbury Farms, situated on dark blue clay ; the sands and masses 

 of the compact gravel reappeared a little south of the road from 

 Fernham to Shilhngford, thus resting on the clays. The Baulking 

 cutting is through a ridge of blue clay, of which the inclination is 

 east, as marked by one or two hard pyritous bands. South of the 

 Railway there is a tract of furze land, where the clay seems to pre- 

 sent a passage upwards into laminated sands. Uffington is on the 

 blue clay, in which on the south of the village is a brick and tile 

 yard, the beds consisting of a tenacious blue clay, and requiring an 

 admixture of sand, which is brought from Alfred's Hill. From 

 Uffington to the chalk there is a level of nearly a mile, affording no 

 section, but the soil consisting of clay. With the rise of the ground 

 the gault was distuictly marked, succeeded by upper greensand, form- 

 mg a distinct under-terrace, to the lower chalk. Ha\ing traced the 

 sands and gi'avel beds as far as the ridge overlooking the stream 

 north of Gaun's Bridge, we thought it possible that they might pass 

 beneath the clays of the Baulking cutting, for in the total absence 

 of fossils, as far as we were able to ascertain, this mass of clay might 

 be either that of Kimmeridge or the gault. 



From Uffington we went to the summit of the chalk escarpment 

 at Uffington Camp, followed the old Ridge-road for a short way, 

 turned down to Compton Beauchamp, and followed the under-terrace 

 of upper greensand as far as Ashbury, and then crossed the valley by 

 North Mill and Stainswich Farms to Shrivenham : the whole of the 

 interval between the base of the chalk and the Canal is a flat clay 

 valley. The coral rag rises close to the village, at the back of Lord 

 Barring-ton's stables, where it is quarried. 



We rejoined Prof. Forbes, Mr. Prestwich, and Mr. Tylor at Shri- 

 venham ; they had ^dsited the reputed Portland quarries at Stamford, 

 and ascertained that they belonged to the coral rag, and then, follow- 

 ing the line of the superincumbent Kimmeridge clay, had traced it 

 passing beneath the sands of Alfred's Hill : the determination of this 

 point was a most interesting one in the relations of the Farringdon 

 deposits, and one which Mr. Shai'pe and myself had been unable to 

 ascertain by Gaun's Bridge. From this too it was clear that the 

 expanse of blue clay, of the hue of the Great Western Railway, in 

 which are the Baulking and other cuttings, belongs entirely to the 



