PRESTON : SURFACE GEOLOGY NORTH . OF GRANTHAM. 



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district. This being so the next question is, When and why did the 

 river leave this valley and take a directly opposite course? Now, if 

 we walk along the valley between Honington and Ancaster, we shall 

 not only find sands and gravels and alluvial deposits indicative of the 

 work of an ancient river, but we shall come across two small streams 

 which rise in close proximity to each other, but which take opposite 

 directions of flow, one taking a westward and the other an eastward 

 direction. Remembering, then, that when the old river ran through 

 this valley there must have been one gentle slope towards the east, 

 we are at once struck with the fact that the watershed dividing these 

 streams must have been formed at a later date than the valley. 



Further, if we visit the railway cutting at Ancaster, we there find 

 the limestone rocks bent into a long curve, which is well seen to 

 form a sort of hog's back hill running across the valley ; in the next 



cutting, and again on the Wilsford Road, the same uplifting of the 

 r ocks is noticed, 



that 



uplift of the rocks has caused the elevated watershed separating the 

 Jines of flow of the two streams, but also that the Witham may trace 

 its departure from the Honington Gap to the period when these 

 folds had got sufficiently high to stop the general flow of water. 



Of course, this would be a 



occupyin 

 <pt. 1896 



very gradual process, possibly 

 arstun of the Witham and the 



