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OeoJogical Society. 



with both of which they are conformable. They also occur in the 

 neighbourhood of Appleby, and in the Sedbergh district. They are 

 divisible into a lower group of black and dark grey and blue Grap- 

 tolite-bearing shales, interstratified with hard bluish-grey mud- 

 stones containing Trilobites and other organisms, and an upper 

 group of pale greenish-grey shales, with thin bands of dark Grap- 

 tolitic shales. The lower group (Skelgill Beds) is well seen in the 

 stream which runs past Skelgill Farm, and enters Windermere near 

 Low Wood ; while the upper group (Browgill Beds) occurs fully 

 develo]:ied in the Long Sleddale Valley, and its beds are very fossili- 

 ferous in Browgill. 



The authors divide these shales into a series of fossil-zones in the 

 following order : — 



r TT / B^ 2 

 Upper \ -n, , 



/ Browgill Beds -"i \^ 7, v t^t . 



^ -P J B« 2 zone of Monograptus cnspus. 



I Ijower I -g^^ ^ turriculatus. 



I ( f Ac 5 Bastrites WMximus. 



Stockdale 

 Shales 



Ac 4 — 

 Upper ■{ Ac 3 — 



I Ac2 — 



Acidaspis erinaceus. 



Skelgill Beds ^ 



— MoiograjJtus spinigerus. 



— Ampyx aloniensis. 



\ Ac 1 Monogmpfus Glingani band. 



( Ah (S Barrel! band. 



I A^; 5 zone of Monograptus convolutus. 



^•-i^-, J A6 4 Phacops glaber. 



Miciaie -\ j^j_ o Monograptus argentcus. 



I Ab2- -— EncrinKrics puwtatiis. 



yAh 1 Monograptus jinihriatus. 



T J Aa 2 Bimorphograptus confertiis. 



Aa 1 — — — Biplograptus acuminatiis & 

 Atrypa flexuosa. 



Of these zones, the lowest varies, occurring as a thin limestone in 

 Skelgill, with Atri/pa jlexuosa, n. sp., and as Graptolitic shale at 

 Browgill with Diplograptus aciiminatus, Nich. The others appear 

 to run persistently across the district, with the exception of the 

 zone of liastrites maccinms, which has only been discovered in the 

 Sedbergh area. The thicknesses, lithological characters, and fossil 

 contents of these zones were considered, and comparisons made 

 between these beds and the corresponding deposits of other areas. 

 The whole group attains a thickness of from 250 to 400 feet, of 

 which the Skelgill beds usually make up about one quarter. 



The authors correlate the Graptolite-zones with those of the 

 Birkhill and Gala groups of Professor Lap worth as follows : — 



Lake District. 

 Zone of Monograptus crispus 



,, ■ turricuhttus 



,, liastrites )naximns 



,, Monograptus spinigerus 



Monograptus Vlingani hn,nd 



Not represented '? 



Zone of Monograptus convolutus 



,, argenteus 



„ Jinihriatus 



,, Diniorp)hograpt'usconfertus = 

 ,, Biplograptus acuminatiis — 



South of Scotland. 

 Zone of M. exiguus. 

 Not separated. 

 Zone of B. maximus. 



,, Monograptus spinigerus. 

 „ Petalograptus comet a. 



Zone of M. gregarius. 



,, Biplograptus vesiculosus. 

 ,, B. acuminatus. 



