62 Broughton Gifford. 



it touches Foss bridge, where Acmari street, part of the Roman 

 road or Fosse way from Bath (Aquce Solis) to Cirencester (Corinium), 

 crosses the stream, and marks the boundary South westward for 

 nearly two miles more. On its emerging from the lake, the river 

 is wholly in Wilts, whilst in the womb of the lake, Gloucestershire 

 must be allowed to claim half the honours of its birth. Winding 

 through a narrow and tortuous valley it reaches, in five miles, 

 Malmesbury, where it is joined by Newnton stream, a not inconsi- 

 derable brook, from Badminton through Easton Grey : in six 

 miles, still tortuous, it reaches Dauntsey ; four more carry it to 

 Christian Malford; one more to the Great Western Railway; three 

 more to its junction with the Marden, a stream receiving various 

 contributions from the western slopes of the Marlborough Downs, 

 communicating with the lake at Bowood and flowing by Stanley 

 Abbey : two miles with a wide loop take it to Chippenham ; five 

 more, with many a bend, to Lacock Abbey, four and a half more 

 somewhat straighter to Melksham, two and a half, also pretty direct, 

 to Monkton. In all, thirty-three miles from Estcourt lake to 

 Broughton. 



About seven miles south-west of Cirencester on the Roman way, 

 where it crosses the Thames and Severn canal, in the parish of 

 Kemble, is the source of the river Isis, or rather of the Thames. 

 Both rivers rise in the same stratum, stone corn-brash or bastard 

 Oolite. The water-shed between the two sources (divortium aquarum), 

 turning the Avon to the south and the Thames to the east, is a 

 spur of the Cotswold range, thrown out from the main line by way 

 of Rodmarton, into the clay vale, bounded by Minety to the east and 

 by Somerford to the west. 



It has been held by Bergmaun that, in mountain chains running 

 north and south, the western slope is most abrupt, while in chains 

 running east and west the southern slope is the steepest. 1 What- 

 ever be the correctness of this law, here there is certainly an 

 example of it. The direction of the Cotswold range is S.S.E. by 

 N.N.W. and its steepest side looks west, while the inclination on 



1 The most striking example of the great geographer's theory is the Scandi- 

 navian mountain chain, with its scarped precipices facing the Atlantic. 



