A HISTORY OF DURHAM 



C. The Magnesian Limestone Region, between the last-named and 

 the sea and bounded on the south by an ill-defined line curving from a 

 little west of Darlington to the Hartlepools. Until about the middle of 

 last century this was a purely pastoral district, but now many collieries 

 have been opened out in it. 



D. The Red Region, between the Lower Tees and the Magnesian 

 Limestone Region. This is the salt district. 



TABLE OF STRATA IN DURHAM 



Period 



Recent 



Formation 



River Alluvium, Peat 



Marine Alluvium . 



Character of Material 



Mud, silt, gravel, peat : border- 

 ing streams and in hollows 

 (old lakes) 



Shingle, beach sand, blowing 

 sand, mud 



Approximate 



thickness 



in feet 



up to 30 

 up to 50 



Old River Drift 



Pleistocene 

 (Drift) 



Old Marine Alluvium 

 Later Glacial Deposits 



Older Glacial Deposits 



Gravel, sand, loam, clay, etc., 

 of ancient river terraces . 



Raised beaches 



Gravel, sand, ' leafy ' clays, 

 cave-earth (?) 



Boulder clay, some rare thin 

 sands and gravels .... 



up to 50 

 up to 30 



up to 250 

 up to 200 



Salt-Mea- 

 sures (Trias 

 above, Up- 

 per Permian 

 below) 



Keuper Red Sandstones and 

 Marls passing downwards in- 

 to similar Permian Sandstones. 



etc. 



Mostly red rocks with deposits 

 of rock salt, gypsum, anhy- 

 drite, and thin magnesian 

 limestones towards the base 



Magnesian Limestone 

 Marl Slate . 



Often concretionary 

 Flaggy calcareous beds 

 fish remains 



with 



Permian 



Yellow Sands (' Quicksands ') . 



Generally yellow but some- 

 times dark-coloured, more or 

 less incoherent, water-bear- 

 ing sandstones .... 



up to 800 



up to 15 

 (usually 3) 



up to 104 



Carbonifer- 

 ous 



Coal Measures : down to the 

 Hutton Seam inclusive 



Coal Measures : down to the 

 Brockwell Seam inclusive 



Lower Coal Measures or Gan- 

 nister Beds. Millstone Grit 



Bernician or Carboniferous 



Limestone Series 

 Basement beds (so-called) . . 



Sandstones, shales, coals and 

 fire-clays 



Sandstone, shales,' coals and 

 fire-clays 



Sandstones, shales, few coals, 

 occasionally beds of 'gan- 

 nister,' sandstones, shales, 

 rare coals 



Sandstones, shales, fire-clays, a 

 few thin coals, limestones . 



Coarse breccia 



together up 

 to 5,500 



variable 



Silurian 



Exact horizon unknown (Stock- 

 dale Shales [?]) . 



' Slate-pencil ' Shales 



thickness 

 unknown 



The scenery of these regions is as characteristic in each case as the 

 industries which each supports, and will be noted under separate heads 



