A HISTORY OF NOTTINGHAMSHIRE 



THE SUPERFICIAL DEPOSITS 



The study of the superficial deposits is a very complicated matter 

 in which but little progress has been made. They include Boulder Clay, 

 gravels and associated sands and boulders, alluvium, blown sand and 

 deposits in old meres and in fissure caves. 



i. Boulder Clay is an unstratified clay containing large stones, which 

 may be rounded, angular or scratched, and include some which are 

 foreign to the district. Its distribution in Notts is almost entirely con- 

 fined to the southern and eastern borders. In the south it caps an escarp- 

 ment of Marlstone except along the earlier formed valleys, where it 

 descends to lower levels, as at Stanton-on-the- Wolds. Further north it 

 descends to the limit of the Lower Lias escarpment, and still further north 

 to the highest Keuper escarpment. Within these limits, except at one 

 locality, there is nothing but gravel. Two varieties of Boulder Clay 

 have been observed during the excavation of the cuttings and tunnel for 

 the Midland Railway near Stanton and Plumtree. The lower of these is 

 50 feet thick and encloses fragments from the surrounding solid rocks, 

 with foreign pebbles from various members of the Carboniferous system. 

 It rests at a height of about 200 feet upon Black Shales which have been 

 contorted in a direction showing pressure from the north-west. On these 

 grounds it may be considered to have been brought by ice, forced to 

 travel in a south-east direction. Associated with the lower Boulder Clay 

 was an enormous block of Millstone Grit 1 ; and a mass of basaltic rock 

 described by Mr. Toplis in i8i4 2 between Barton and Thrumpton is 

 probably another large boulder. 



An upper Boulder Clay rests, near the entrance to the Stanton tunnel, 

 at a level of 230 feet upon a floor of Lias limestone which is striated in 

 a direction E.N.E. to W.S.W. and contains, amongst other boulders, 

 fragments of chalk and flint. The ice that brought it is judged therefore 

 to have come from the E.N.E. The same kind of Boulder Clay forms 

 the summit of the cutting at Plumtree at a somewhat lower level. It is 

 this also that lies on the rocks of lower geological horizons in the north- 

 east. The exceptional instance of a Boulder Clay not on the borders of 

 the Trent basin is at Kneesall Hill, 3 reaching a height of 300 feet. 

 This clay contains fragments of Trias Sandstone, Liassic and Oolitic 

 Limestones and Chalk, mixed with rounded or striated fragments of 

 Carboniferous rocks with slate and quartzite probably derived from an 

 earlier Boulder Clay. The rest of the country has not been examined 

 with sufficient care to enable it to be said that no other exception can 

 be found. 



In other cases towards the south-west old stratified clay has been 

 churned up, and pebbles, usually of quartzite, forced into it on the spot. 

 Such cases for instance are known in relation to the Permian Marls west 

 of Bulwell at a height of about 170 feet above O.D.; and at Wilsthorpe, 



1 Deeley, Stuart. Journ. Geol. Soc. vol. xlii. * Annals of Pbiksophy, vol. iii. 



3 Geol. Survey Mem. sheet 83. 



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