THE BASIN OF THE THAMES. 



147 



Thames may be said to be made up of parallel strips varying in width, but all 

 striking from the south-west to the north-east. A broad band of cretaceous rocks 

 extends, however, to the south, having its root in the " plain " of Salisbury, and 

 forming the range of the North Downs, which separates the tracts of the Weald 

 from the valley of the Thames. The eastern extremity of the county of Kent, 

 which may be likened to the prow of England, forms part of this e*xtended band 

 of chalk. These North Downs, together with the culminating points rising upon 

 the uplands from which they extend eastward, form the highest elevations within 

 the basin of the Thames. Their height, however, in no instance exceeds 

 1,000 feet.* The chalky uplands to the north of the river are even less elevated, 

 and only the Chiltern Hills, which stretch north-eastward from the Thames, above 

 Reading, can compare with them, their culminating point, Wendover Hill, attain- 



Fig. 80. — CiRfiXCESTER A>fD Thames Head. 

 Scale 1 : 175,tJ00. 



W.of G. 



1° 50 



2 Miles. 



ing a height of 905 feet. Formerly these hills abounded in timber, especially 

 beech, and afforded shelter to numerous highwaymen. To put the latter down, and 

 to protect the inhabitants of the neighbouring parts from their depredations, a 

 " steward " was appointed under the Crown. For several generations past the 

 duties of this officer have ceased, but his office remains, in order that it may be 

 conferred on any member of Parliament, not otherwise disqualified, who is desirous 

 of resigning his seat. The applicant, by accepting office under the Crown, 

 renders his seat in Parliament vacant, and a writ for a new election is ordered. 



The basin of the Thames has singularly varied in extent in the course of 

 geological ages, in accordance with the oscillations of the land and the displace- 

 ments of the sea. Whilst England still constituted a portion of the neighbouring 



* Milk Hill, 967 feet; Inlvpen, 973 feet; Leith Hill, 967 feet. 



