THE GEOLOGY OF CAMBRIDGESHIRE. 



By W. G. FEARNSIDES, M.A., F.G.S. 



THE geology of Cambridgeshire, so far as the underlying 

 strata are concerned, is not complicated ; the superficial 

 deposits, however, exhibit considerable variety, and their 

 origin is still in many cases a subject for discussion. 



The stratified rocks of Cambridgeshire form part of the 

 great mass of secondary strata which extends in an unbroken 

 line from the Yorkshire coast to that of Dorsetshire. In the 

 tract of which Cambridgeshire forms a part, their general 

 strike is nearly north-east and south-west, and as the beds dip 

 gently towards the south-east (at angles which approach hori- 

 zontality) the older strata lie to the north and west of the 

 county and the newer ones to the south and east. To the 

 north-west of a line drawn from near Littleport to Gamlingay 

 the rocks mainly belong to the Jurassic system ; to the south- 

 east of that line to the Cretaceous System. 



Complications are introduced by folding, unconformabilities, 

 and the existence of outliers. An anticlinal fold brings up 

 a considerable mass of Jurassic rocks in the neighbourhood of 

 the hamlet of Upware. An important unconformity occurs at 

 the base of the Cretaceous rocks, causing the lower Cretaceous 

 rocks to rest upon different members of the Jurassic System, 

 while a smaller unconformity occurs at the base of the Chalk. 



