AND ASSOCIATED PEIiMIAN ROCKS OF DURHAM. 



205 



The stratigrapliical arrangement adopted is that which is now 

 generally accepted for the Permian strata of Durham, viz. : — 



TABLE I. 



CD 

 'f-< 

 CD 



CO 

 a 

 d 

 o 



to 



CD 



a 



CD 



a 



bO 



o 



3 



CD 



Pn 



SUB-FORMATION. 



LOCALITIES IN NORTH DURHAM. 



5. Upper Limestone. 



Half-way House, Building Hill, Ful- 

 well Hill, and Roker, near Sunderland ; 

 coast from Roker to Marsden, &c. 



4. Middle Limestone. 



Humbleton Hill, Tunstall, Galley's 

 Gill, &c,, near Sunderland; coast for 

 several miles south of Rykope Dene ; 

 Trow Rocks, near South Shields ; Down 

 Hill, near West Boldon. 



3. Lower Limestone. 



Hartley's Quarry, Pallion, and Clax- 

 heugh, near Sunderland ; Frenchmen's 

 Bay, Down Hill, Pensher Hill, Hough- 

 ton -le- Spring, Moorsley, Pittington, 

 Running Waters, &c. 



2. Marl-slate. 



Cullercoats, Claxheugh, Offerton, Sher- 

 burn, &c. 



1. Lower Red Sandstone. 



Claxheugh, Offerton, Down Hill, 

 Down's Quarry, Sherburn, &c. 



ANALYSES. 



Sub-fokmation.— LOWER RED SANDSTONE. 



Geological Characters. — A yellow or greyish, usually incohe- 

 rent, and false-bedded sandstone ; sometimes apparently passing 

 into (below) a red, purple, or grey, micaceous, and comparatively 

 hard sandstone. The first-named is essentially a quartzose rock, 

 the grains of which are always more or less water-worn, and 

 coated with oxide of iron ; in some parts it becomes calcareous 

 (analyses 1 and 4). In its incoherent form it is generally present 

 below the Marl-slate, and is sometimes of considerable thickness ; 

 as at the Fulwell "Water Works, one hundred and fifty feet, and 

 Pyhope Pit, ninety-six feet ; at others it is exceedingly thin, as 

 at Wearmouth Pit, five feet, and one of the Seaham pits, three 

 feet ; and occasionally it is absent. The six analyses below are 

 from this portion of the deposit. 



