THE GEOLOGY OF THE DISTRICT 55 



Glacial and Post Glacial Deposits 



The late Dr. Bernard Smith aptly described this area as a ' cockpit 

 where tongues of ice from various directions strove successively for terri- 

 torial rights '. Just beyond its eastern and southern margins considerable 

 areas of boulder clay occur consisting of material brought by ice moving 

 southwards over Lincolnshire and westwards across Rutland into 

 Leicestershire. Ptojecting northwards from the Leicestershire Wolds is 

 a spur capped with boulder clay which reaches almost to the Trent. This 

 seems to have marked the position of the terminal moraine of that selvage 

 of the ice which flowed along the Vale of Belvoir. 



North and west of the Trent only scanty fragments of boulder clay 

 are to be found and these are confined to the higher grounds. The most 

 obvious and at the same time the most southerly of these lies on a series 

 of high points stretching from Blidworth almost to the city boundary. 

 Magnesium limestone occurs in the boulder clay throughout the area. 

 On the eastern side, chalk and oolite are recorded, but on the west these 

 are replaced by boulders from the more resistant portions of the carbon- 

 iferous rocks. Stone of more distant origin have come from the Whinsill 

 and the Lake district. 



Though boulder clay is scanty, gravels abound. The higher level 

 gravels spread Uke outwash sheets on both the Bunter and Keuper out- 

 crops, and their soils yield numerous facetted pebbles. 



The valleys of the Trent and its tributaries have been excavated out of 

 the surface tipon which these gravels were spread, and in them are found 

 the lower level gravels. The oldest of these occupies a prominent terrace 

 which extending from University Park westwards through Long Eaton to 

 Borrowash. Fragments of a terrace of the same age occur along the 

 south side of the valley at various points from West Bridgford to Newark. 

 At Beeston these gravels have yielded early palaeolithic implements. 



The floor of the major part of the main valley lies about 40 feet below 

 the surface of this terrace. On it Ues a sheet of gravel of variable thick- 

 ness and irregular surface. The more upstanding portions of this are 

 still to be seen rising above the level of the alluvium, thus providing the 

 sites for many of the villages in the vale between Nottingham and 

 Newark. These gravels have from time to time yielded tusks and teeth 

 of the Mammoth at various points as far down stream as Hazelford thus 

 proving that this part of the floor of the valley must have been formed 

 during the ice age. These gravels contain numerous flint fragments which 

 must have come from the chalky boulder clay on the country south of the 

 Trent. 



Since the deposition of these lowest gravels the river has been occupied 

 mainly in filling up the hollows on their surface with resorted gravel and 

 alluvium. During the early stages of this process some of the hollows 

 were occupied by extensive sheets of standing water which in course cf 

 time became filled with peat. This in its turn was covered with alluvium. 

 One such body of water remained until the University College buildings 

 in University Park were erected. This water occupied the site of the 

 western end of the present lake in which it was subsequently incorporated. 



