1845.] 579 



2. Coniston flagstone. This group the author has formerly de- 

 scribed as Brathay flagstone, but now proposes to change its 

 name to Coniston flagstone for the sake of symmetry. No group 

 is better defined than this in the Lake country, and although 

 the Brathay and Coniston quarries are several hundred feet above 

 the preceding grouj), the series may be completed, in consequence 

 of the regularity of the dip, by connecting a succession of quar- 

 ries, and in this way the whole is estimated to be not less than 

 1500 feet thick. 



The mineral character of the Coniston flags resembles that of 

 the lower Denbigh flags, but is more altered by slaty cleavage *, 



Mollusca. 



Orthoceras, three smooth species, like Orthis vespertilio 



those from the lower Bala lime- O. virgata 



stone O. actoniEe 



Litultes cornu-arietis Orthis n. sp. (named in MS. crucialis), 



Euomphalus ? perhaps two species under the same 



Turritella, or Terebra name 



Turbo? O. radians 



Lepteena depressa Orthis n. sp. ? with fine simple ribs 



Leptsena n. sp., decussated Orthis n. sp., same as from Dudley, a 



L. sericea curious rough species 



L. transversalis and another Atrypa (Spirifer), resembling S. acumi- 



L. (Orthis) grandls, Sil. Syst. nata 



Orthis canalis A. (Spirifer), a smooth species, ? new 



O. alternata ? Atrypa affinis 



O. testudinaria Spirifer n. sp. named in MS. 



O. flabellulum ^ S, n. sp. ? small variety of S. radiatus 



Crustacea. 



Cytherina laevigata A. tyranniis 



Paradoxides quadiimucronatus Illoenus {Bowmanni, MS.; called Bu-' 



Calymene Blumenbachli mastiis Barriensis in a former list) 



Calymene n. sp. Brontes, undescribed species {vide Port- 



Asaphus Powisi lock's report). 



The corals, both as to species and numbers, are precisely similar to those 

 north of the Berwyns. 



In the abundance of Leptcena depressa, L. transversalis, Orthis radians, and 

 above all, O. inflata, with spiral shells, and Lituites cornu-arietis, there is an 

 analogy with the beds north of the Berwyns : but the presence of Orthis Actonia 

 and O. virgata, with ^jamyer (crwc/a/Zs), which are also plentiful, approximates the 

 group to that from Bala and the Coniston limestone; it resembles also these latter 

 beds in possessing the smooth Orthoceratites, Encrinites, and Illcenus {Bowmanni), 

 but it differs in the scarcity of Orthis canalis, O. testudinaria, and O. vespertilio, 

 and the absence of O. fluhellulum, O. alternata, Spirifer radiatiis, Agnostus pisi- 

 formis, Trinudeus Caractaci, and Asaphus tyrannus (one doubtful specimen of 

 this latter having been found), fossils characteristic of the lower group in Wales. 



An undescribed Paradoxides, a tail of a new Brontes, a curious undiilated 

 fossil (perhaps crustacean), a new Tentaculites, and abundance of Cytherina 

 (a marine Cypris) seem peculiar to the Coniston limestone; and the last is a 

 very interesting fossil, not having been known before in rocks of the Silurian 

 ssi'ies. 



* The author observes, with reference to this condition, that he has observed 

 in the flags in question distinct cases of a second cleavage plane entirely distinct 

 both from joints and bedding. 



VOL. IV. PART III. X X 



