CHAPTER III. 



GENERAL PHYSICAL FEATURES OF THE COUNTY AND 

 DESCRIPTION OF THE GLACIAL DEPOSITS. 



Cambridgeshire is divisible into four natural regions or 

 districts, which are separated by the valleys of the principal 

 rivers that traverse the county ; each district having a different 

 geological structure and consequently presenting different physi- 

 cal features. 



The first of these regions is that comprised between the two 

 tributary streams of the river Cam, called respectively the Rhee 

 and the Bourn or Linton river, the one taking its rise in Hert- 

 fordshire and the other in Essex ; such portions of these counties 

 therefore as form part of the same valley system are included in 

 the area hereafter described. Through the centre of this district 

 runs the river which may be considered the main stream of the 

 Cam^; it rises near Quendon in Essex, and running due North 

 by Newport, Wenden, Littlebury, Chesterford, Hinxton, Duxford 

 and Whittlesford, is joined by the Linton brook at Shelford, 

 whence the united streams flow to meet the Rliee about a mile 

 below Hauxton Bridge. 



The second region lies to the N.E. of the Linton stream and 

 to the S.E. of the Cam or Granta as the river used to be called 

 below its junction with the Bhee ; it includes the high ground 

 formed by the Gog-Magog and Balsham Hills and the hilly 



1 I think this branch has stronger claims to be taken as the main stream 

 than that which is called the Rhee, for it has more important towns on its banks, 

 its course is rather longer, and I believe the valley in which it flows to be much 

 older than that of the Ehee. 



