TRANSACTIONS OF SECTION C. 



675 



[ Upper Old Red Sandstone. Local conglomerates, ' more connected with the 

 Carboniferous than with the Devonian.' No Stigmai-ia.'] 



In 1875, Tate's classification of the upper divisions of the series was set aside 

 ■fcy Professor Lebour in favour of an arrangement more ' natural and convenient.' 

 Professor Lehour abolished the distinction between the Calcareous and Carbona- 

 ceous groups, and threw them together — along with the Tuedian grits of some parta 

 of the county — into a single large series, to which he applied the term Bernician, 

 It is based on the assumption that Tate's two divisions either do not exist in nature 

 or do not persist throughout the county. 



caebonrfekotts limestone series in noethttubekland ; 

 Classification, 1875-1886. 



Lebottr's 



JSernician A large group — which ' cannot be divided in any natural 



manner ' — of limestones, grits and sandstones, shales, 

 and coals ; lower limit, ' a variable one,' not keeping to 

 any one horizon ; thickness, in North Northumberland, 

 2,600 feet (after Tate); in Mid Northumberland, a 

 maximum of ' at least 8,000 feet ' ; in South North- 

 umberland, 2,500 feet (after Westgarth Foster). 



Tuedian As in Tate's classification, but without definition at its 



upper limit. 

 Basement Conglomerates Local. 



It has never been contended, the author believes, that Tate's prior classification is 

 not applicable to North Northumberland. It is now, as a result of the labours of the 

 Geological Survey, found to be equally applicable to South Northumberland, and 

 to the whole of what deserves to be distinguished as the Northumbrian Type of 

 the Carboniferous Limestone series — in contrast with the Yorkshire type and 

 Scottish type. It is amphfied in some not very important details, as set forth in 

 the following table : — 



-CAEBONrFEEOUs LiMESTONB Seeies — NoETHUMBEiAN Ttpb (Northumberland, 

 East Cumberland, and Liddisdale. 



Upper 



Limestone 



Series. 



Lower 



jLimestone 



Series. 



/ Felltoj) or Upper Calcareous Bivimon : — From the Mill- 

 stone Grit to the zone of the Great Limestone. Sand- 

 stones and shales ; one or more beds of marine 

 limestone, including the Felltop Limestone ; some 

 ■{ coals 



Calcareous Division : — From the great Limestone to the 

 bottom of the Dun or Redesdale Limestone-. Many 

 beds of good marine limestone ; sandstones and 

 \ shales ; coals 



Carbonaceous Dirisiofi (Scremersfon Beds of North 

 I Northumberland :^From the Dun or Redesdale Lime- 

 stone to Tate's ' Tuedian Grits' Strata prevalently 

 carbonaceous ; limestones chiefly thin, many of them 

 containing vegetable matter ; coals .... 



Tmdian Division : — Upjyer Tuedian or Fell Sandstone 

 Group, the ' Tuedian Grits ' of Tate : — From the Car- 

 bonaceous Group to the Cement-Limestones. Great 

 belt of massive grits (Tweedmouth, Chillingham, the 

 Simonside and Harbottle Hills, the Peel and the Bew- 

 castle Fells). Shales greenish and reddish as well 

 as carbonaceous-grey ; coals rare, thin, or absent 



Lower Tuedian or Cement-Limestone Group : — From the 

 base of tlie grits doivnwards. Cement -stone bands 

 passing (Rothbury, Bewcastle) into limestones ; 

 coals very rare ; generally some coloration of the 



shales and sandstones 



. Basement Conglomerates ( Upper Old Red Sandstone) ; 

 local 



Feet 



350-1,200 



1,300-2,500 



800-2,500 



{ 



500-1,600 



500-1,500 



X X 2 



