PROCEEDINGS OF THE COTTESWOLD CLUB 



8l 



The Fuller's Earth is lost east of the watershed of the 

 Windrush. It is cut off by the north and south fault on 

 the western side of the sub-basin of the Dickler, ranging 

 from one mile south of Condicote to Wagborough Huish, 

 a little south-west of Upper Slaughter. 



No Fuller's Earth is known east of the watershed that 

 divides the Windrush from the Evenlode. 



This may be accounted for by the complicated system of 

 west and east Faults of Donnington, Upper Swell, Stow- 

 on-the-Wold, and Lower Swell, the waters from which 

 enter the Lower Lias Valley near Lower Slaughter, 

 there meeting the main stream from Bourlon-on-the-Water 

 at New Bridge, opposite Rissington. 



The Evenlode largely depends upon its supply from the 

 numerous tributaries flowing over the broad plain of the 

 Lower Lias from Moreton-in-the-Marsh to its entrance into 

 the narrow, valley of Ascot and Charlbury, along which it 

 drains the Inferior Oolite, and also the spread of Great 

 Oolite to the north and east, entering the Oxford Clay 

 at Blaydon, over which it traverses for four miles, joining 

 the Thames half-a-mile south-west of Cassington. 



The south-west and north-east strike of the well- 

 defined and parallel groups of the Jurassic Rocks ranging 

 from the Lias to the close of the Great OoHte series, in- 

 cluding the Cornbrash, is a marked feature in the phvsical 

 structure of the Upper Thames district between the south- 

 western and north-eastern sides of the watershed. 



This Calcareous Zone is succeeded by the parallel and 

 Impervious Oxford Clay, the outcrop of which uninter- 

 ruptedly ranges from Crudwell, nine miles west of 

 Cricklade, close to the w^estern divide, to Stratton Audley, 

 north of Bicester. Along this defined outcrop are placed 

 the towns of South Cerney, Fairford, Witney, and Bicester. 

 The southern outcrop ranges from a little west of Purton 

 to Highworth, Faringdon, Oxford, and Quainton, i8 miles 



