A HISTORY OF DERBYSHIRE 



MILLSTONE GRIT 



The Millstone Grits rest conformably on the Yoredale Shales, and 

 are found in the northern part of the county and on the east and west 

 side of the Pennine Chain. They extend as far south as Little Eaton, and 

 a small patch occurs in the neighbourhood ofTicknall and Melbourne 

 in the south. The alternation of hard sandstones with beds of soft shale 

 has produced a type of scenery different from that of the Mountain 

 Limestone. The outcrop of each sandstone bed forms a long ridge with 

 a sloping surface on one side in the direction of the dip, and on the 

 other side a steep face or escarpment which is almost vertical. Below 

 the escarpment the ground has a more gentle slope, and often a broad 

 valley is hollowed out in the beds of shale underlying the grit. These 

 escarpments are known locally as edges, and form very well marked 

 features in the landscape. Amongst the finest of them are Curbar, 

 Froggatt, Bamford and Derwent Edges on the eastern side of the county. 

 The highest part of the county is composed of Kinder Scout Grit. It 

 forms a large outlier which is roughly triangular in outline, and is 

 situated in the north. This tableland, though dignified by the name of 

 the Peak, contains no pointed hills. The rocks dip inwards towards 

 the middle of the plateau, and to this fact the outlier probably owes its 

 survival. The escarpments which bound the plateau form irregular and 

 rugged cliffs, through which streams of water have cut deep gorges 

 called cloughs. The scenery is wild and the surface of the plateau is 

 covered with peat. It is strictly preserved, but, owing to the efforts of 

 a local footpaths association, the pedestrian may enjoy a walk from 

 Hayfield either to the Snake Inn or to Edale through some of the 

 characteristic parts of the scenery. 



The Millstone Grit series consists of five thick sandstones or grits 

 parted by shales, with which thinner sandstones are intercalated. The 

 grits vary in character from a fine grained sandstone to a conglomerate, 

 and consist of quartz, orthoclase, felspar and white mica. Dr. Sorby 

 considers that they have been formed from the disintegration of granites 

 and schists, and have been deposited by currents from the north-east. 

 From the Kinder Scout Grit near Whatstandwell the author obtained a 

 pebble of foliated rock or schist, which is well rounded and measures 

 6x3x2 inches. 



The fifth or lowest grit, called Shale Grit by Farey because of the 

 numerous bands of shales it contains, consists of thick massive sandstones 

 which often pass into a conglomerate. The shales when traced some 

 distance are found to thin out. This grit attains a thickness of 500 or 

 600 feet around the Peak, thins out towards the south, and is absent in 

 some places. The Shale Grit forms round the Kinder Scout Grit of the 

 Peak a broad plateau, which is deeply channelled by rivers and brook 

 courses. The outcrops of the shale bands are marked by small terraces 

 which run along the steep sides of the valleys. Numerous landslips have 

 taken place along the course of the river Alport. The largest slip is 



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