of Oolitic gravel. AtFoss Farm, Driffield, is a hill of sand covered 

 with fane, which Mr. Bravender has pointed out to me as representing 

 the Kelloxcay Rock, and from which he has obtained a specimen of 

 Ammonites Hcrveyi. 



5. — At Driffield cross-ways we may see the Corn Brash in the 

 small quarries from which the road stone is obtained, and in descend- 

 ing the hill towards Cirencester we pass over to the Forest Marble, a 

 thin-bedded stone, well shewn in the quarries at Preston, from which 

 much of the roofing stone and planking so extensively used in the 

 neighbourhood are obtained. Frequent beds of marly-clay alternate 

 with the stone, one of which, on Mr. E. Bowly's Farm, at 

 Siddington, is worked as a brick-field. One of these beds of clay is 

 usually found dividing the Forest marble from the Bath freestone, and 

 consequently represents the Bradford Clay. Beyond Stratton our 

 road lies over the Bath freestone (or " Hampton stone") as far as 

 Highgate, where several deep valleys expose the Stonesficld Slate, 

 Fuller's Earth, and Inferior Oolite. 



The quarries near Birdlip also exhibit the Inferior Oolite, and the 

 remainder of the road to Gloucester rests upon the Lias. 



If an Artesian well (such as that now in progress at Southampton) 

 were attempted at Swindon New Town, it would pass through all the 

 above-mentioned strata, from the Kimmeridge clay to the Lias, in 

 the same order in which they are passed over by the Ermine way, 

 reaching the surface of the Lias at a depth of about 1000 feet. 



The same system of strata forms a continuous tract of country, 

 having similar characters, extending from Scarborough and Whitby, 

 on the Yorkshire coast, to Lyme Regis and the Isle of Portland, on 

 the coast of Dorsetshire. 



Having said thus much on the Cotteswolds district, I will refer 

 now more particularly to the subsoils of the College Farm. 



When I first visited Cirencester in August, 1845, I obtained from 

 Mr. Bravender an account of the neighbouring rocks and quarries, 

 more particular than was afforded by any published document ; for 

 the geological maps represent by one colour all the country between 

 the Oxford clay and Inferior Oolite, although in the interval there 

 are four strata containing different suites of fossils, and presenting an 

 entirely different geological and agricultural character. 



On a small part of the College Farm the Bath freestone forms the 

 subsoil, and in the deepest hollow is a deposit of Oolitic gravel; but in 

 almost every field the subsoil consists of clay and " stone brash" 

 intermingled, for not only do the beds of clay alternate with layers 

 of stone, but the same led is at one place entirely composed of stone, 

 and within a few yards the stone may thin out and give place to clay. 

 " Stone brash " is the local name for rubbly limestone ; even the most 

 solid beds become " brashy " near the surface, owing to the action of 

 frost and rain water. The stone brash of the College Farm becomes 

 hard and " planky " at a small distance from the surface, like the 

 Forest marble of the Preston quarries, and is part of the same 

 formation. Hundreds of tons of this stone have been raised for 



