46 SCIENTIFIC SURVEY OF NOTTINGHAM AND DISTRICT 



Nottingham they curve and converge towards one another (see map inset 

 opposite page 48) with the result that half the formations are to be found 

 within the city boundaries. As the Mesozoic rocks continue westwards 

 they cover up the outcrops of the Palaeozoic rocks south of the latitude 

 of the city. 



H.H.S. 



Carboniferous 



The Carboniferous rocks of Derbyshire exhibit in their lithology a 

 three-fold division of Limestone, Grits and Coal Measures which reflect 

 in the contrasting soils, vegetation and land forms three very character- 

 istic types of scenery. 



The dominant structural feature of the region is the Pennine anticline 

 of which the Derbyshire Dome forms the southern termination. The 

 prevailing easterly dip of the Carboniferous strata is broken by subsidiary 

 folds marked by inliers of limestone at Crich and Ashover, and further 

 minor folds occur in the Coal Measure basin to the east, constituting 

 the southern part of the Yorkshire, Derbyshire and Nottinghamshire 

 Coalfield. The fact that these folds when traced southwards develop 

 a Charnian trend suggests that older trend lines were re-emphasized by 

 post-Carboniferous movements. 



Carboniferous Limestone 



The Carboniferous Limestone dome of Derbyshire is perhaps the most 

 visited area of ' Mountain Limestone ' in the country. The subdued 

 topography of the limestone plateau is accentuated by the deeply notched 

 dales, whose streams are, as in the days of Isaac Walton, still famed for 

 their fishing, and no visit to the district could be deemed complete with- 

 out seeing Dovedale or some other such scenic gem of Derbyshire. 



The massive crystalline limestone is of considerable purity and ex- 

 posures in natural river cliffs, caverns, railway cuttings and extensive 

 quarries facilitate a closer study of the rock. 



With the exceptions of a small area of hmestone near Buxton which 

 may belong to the upper half of the Seminula zone (S2) the 1,500 feet of 

 limestone exposed are of the Dibunophyllum zone (D). On the whole 

 the upper beds are of darker hue and are more silicified than the lower 

 and the former are also the more fossiliferous. Lonsdaleia floriforinis, 

 Lithostrotion of various species and other reef building corals are suc- 

 ceeded by gigantic productids. The grey crinoidal ' marble ' is in evi- 

 dence in many a Derbyshire mantlepiece and in the paving of corridors 

 and quadrangle of Nottingham University College at University Park the 

 stone from Hopton Wood quarry has been used with effect. 



A feature of the Derbyshire dome is the evidence of contemporaneous 

 vulcanicity in the form of lava flows (the ' toadstone ' of the lead miner), 

 bedded tuffs and associated necks of agglomerate. In addition there are 

 sills of Olivine dolerite of somewhat later date which together with the 

 ' toadstones ' have been quarried for road metal. The mining of lead 

 ore in Derbyshire is of great antiquity and the laws governing the working 

 of galena and the associated gangue minerals in the Wapentake of 



