GEOLOGY 



just over the Derbyshire border, Keuper Marls have been thus treated 

 from a level of 54 feet to 128 feet. In these cases only the pebbles 

 seem to have been brought from a distance, and it is rather uncertain 

 at what stage of the history they arrived. 



2. The gravels are of two kinds, those connected with the river 

 Trent itself and those not so connected. The latter are the most wide- 

 spread of all the superficial deposits and present the greatest difficulties, 

 whether considered to have been formed on the land or beneath the sea, 

 especially as they have not yet been sufficiently studied. Two sources of 

 these gravels may be recognized, corresponding more or less closely to 

 those of the two Boulder Clays, viz. one from the west or north-west and 

 one from the east or E.N.E. 



The gravel from the west is a high level gravel. The lowest and 

 most southerly spot at which indications of it have been met with is on 

 the hills to the west of Arnold, where comparatively large boulders of 

 Carboniferous limestone and volcanic rocks lie on the surface of the 

 Bunter Pebble Beds at a height of 300 feet. At a spot a mile north of 

 Watnall loose and large pebbles lie in a patch on the Magnesian Lime- 

 stone at a height of 440 feet. A mile further north commences the high 

 ridge of the Long Hills, composed at the base of Lower Red Sandstone, 

 and covered to the top with gravel, including large rounded boulders of 

 syenite, like that of Buttermere, and smaller ones of a felspar-porphyry 

 and of a compact lava resembling the Iron Crag lava of Keswick. This 

 ridge rises to a height of over 500 feet. Where the Pebble Beds come on 

 in Annesley Park they are capped by a long ridge of gravel rising to 

 580 feet along the nearly level top. About the middle of this ridge is a 

 sand pit, showing on the east side a quantity of white sand, 1 irregularly 

 bedded, with a streak of broken coal fragments, overlying obliquely a 

 pebbly mass in which the bulk of the subangular fragments, some of 

 fairly large size, consist of the Permian limestone with casts of Schizodus, 

 and of pieces of Carboniferous sandstone. A portion of this limestone 

 gravel, which differs in no other way from the rest, is consolidated into 

 an irregular pipe of rock, probably by the action of percolating water 

 dissolving and redepositing the calcareous matter from the finer particles. 

 At the north end of the plantation is a long gravel pit where the boulders 

 are of various sizes and materials, with a similar consolidation in parts, 

 and surrounding in one spot a large mass of Pebble Bed rock. Further 

 on in the same direction the gravel-covered hills rise to the highest point 

 in the county, in the Robin Hood's Hills, at 625 feet. From this point 

 eastward to Blidworth there are other gravel pits, in one of which the 

 gravel is again consolidated as in a vertical pipe, and just before reaching 

 Blidworth are seen the well known ' Druidical Remains,' which consist 

 of similar consolidated masses, shaped by the hand of man and containing 

 as before many fragments of Permian limestone. Beyond this point the 

 gravels have not yet been traced. Further north at Mansfield Woodhouse, 



1 Cf. Deeley, loc. cit. 

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