264 



STKATIGRAPHICAL GEOLOGY 



Subdivisions. Zones. Stages. 



Upper Calcareous division (from the Millstone grit ^ 

 to the top of the Oxford limestone). Sand- 

 stones and shales with some coals and one 

 or more beds of marine limestone, 1200-2000 . 



e. Lower Calcareous division (from Oxford lime- 

 stone to base of Dun or Redesdale lime- 

 stone). Sandstones and shales with coals 

 and many beds of marine limestone, 800- i ; 

 1000 yX 



d. Carbonaceous division (Scremerston Beds). 

 Strata prevalently carbonaceous ; limestones 

 chiefly thin, many containing carbonaceous 

 matter ; many coal-seams, 800-2500 . . 



c . Upper Tuedian or Fell Sandstone Group : a belt 

 of massive grits with green, grey, and reddish 

 shales ; coals rare and thin, 500-1600 . . SJ 



b. Lower Tuedian or Cement-stone Group : sand- 

 stones and shales with bands of cement-stone 

 passing into limestones near Rothbury and Tournais- 



Bewcastle, 500-1500 C iau. 



a. Basement conglomerates (Upper Old Red 



Sandstone), 0-500 ? Z 



Tuedian Series. a. The basement conglomerates occur locally 

 round the Cheviot Hills, and are by some referred to the Upper 

 Old Red Sandstone, but they pass up into the overlying sandstones, 

 and certainly form a local base of the Carboniferous System. They 

 are of a reddish-brown colour, and contain rolled pebbles of the 

 Cheviot porphyrites. 



b. This group consists of yellow and reddish sandstones, grey 

 and purple shales, greenish sandy clays (sometimes full of hard 

 siliceous concretions), and beds of hard cream-coloured earthy 

 limestone or cement-stone. In these beds fossils are rare and 

 badly preserved, but Modiola Macadami occurs. Near the top are 

 limestones in which Professor Garwood has found Syringothyris 

 ciispidata, Athyris glabristria, and Orthotetes crenistria, and these are 

 sufficient to indicate the zonal age. 



c. The Fell sandstones form a broad belt of high and rugged 

 country in the west of Northumberland, rising into craggy hills 

 such as those of the Chillingham and Simonside Hills, and the 

 Peel and Bewcastle Fells. These sandstones are divided by bands 

 of shale, and a few thin seams of coal occur. The fossils are chiefly 

 plant remains, but Archanodon Jukesi has been found in the 

 lowest (Harbottle) grit, and Professor Garwood has also discovered 

 a few marine fossils in the lowest beds on the borders of Cumber- 

 land ; these include Camarophoria isorhyncha and Spiriferina 

 laminosa, which in Westmoreland are restricted to the lower part 

 of the Seminula zone. 9 



