768 MR. F. K. C. REED ON THE LOWER PALEOZOIC [NoV. 1 899, 



parts of Scandinavia/ yet the above definition serves our purpose 

 for comparison. The uppermost part of the OrtJioceras-limestone 

 is called the Cystidean Limestone, which is partly equivalent to the 

 Echinosphaerite-limestone Ci of the Russian Baltic provinces.^ 

 Below this comes the main mass of the OrtJioceras-limestone, 

 which in Russia is more or less represented by the ' Yaginatenkalk ' 

 B 3 and Glauconite-limestone B 2. The fauna of the Tramore Lime- 

 stones shows some remarkable points of resemblance with that of 

 the upper part of the OrtJioceras-limestone. Thus the characteristic 

 genera Poramhonites^ AmpJiion, and Glyptocystis are common to both. 



The subgenus of PJiacops called Pterygometopus, represented in 

 the Waterford area by PJi. Jamesii, PJi. Brongaiarti, PJi. truncato- 

 caudatus, and PJi. Bailyi, and in Russia by such species as Pli. 

 sclerops^ PJi. trigonocepJiala, is also a typical and abundant form. 



As regards species, the following are characteristic of both 

 areas : — 3Ionticulipora petropolitana, Poramhonites intercedens, 

 Ampy,v mammillatus, with the more widely distributed forms 

 StropJieodonta imbrex, Rafinesquina deltoidea, OrtJiis (PlatystropJiia) 

 hiforata, OrtJiis calligramma, Plectamhonites sericea.^ To the exist- 

 ence of allied species some foreign palaeontologists have previously 

 drawn attention. Thus Schmidt"^ compares his PJiacops trigono- 

 cepJiala from Stage C 1 with PJiacops Brongniarti ; Holm^ compares 

 Illcenus EsmarJci, Schlotheim, with lUcenus Bailyi, Salter.^ 



I am able further to mention the following additional closely 

 allied or representative species : — 



AsapJius rectifrons, PortL — A. expansus and allies. 

 Am^Mon benevolens, Salt. — A. FiscJieri, Eichw. 

 Agnostus agnostiformis, M'Coy — A. glahrciMs, Ang. 

 CJieirurus gelasinos^is, Portl. — Ch. exsul, Beyr. ' 

 CJi. sp. — CJi. perlongus, Brogg. 



Polypora assimilis, Lonsd. (?) — Polypora f areata, Eichw. 

 Cyhele tramorensis, Reed — Cybele coronata, Schmidt. 

 ''Barrandia PortlocJcii, Salter — Ogygiocaris dilatata, var. Sarsi, Ang. 

 ^Pseudocrania divaricata, M'Coy — Pseudocrania depressa, Eichw. 



Several Waterford species are also comparable with Scandinavian 

 or Russian forms : — 



Am/pyx cf. VolhortM, Schmidt. 



Ampyx ef. PortlocJci, Barr. 



OrtJiisina cf. squamata, Pahl. 



Coscinium cf . proavum, Eichw. 



1 Nathurst, Sver. Geol. Undersokn. Ser. B a, 'No. 4 (1884) ; Moberg, Sver. 

 Geol. Undersokn. Ser. C, No. 109 (1890) p. 18. 



2 Schmidt, Quart. Journ. Geol. Soc. vol. xxxviii (1882) p. 521. 



^ Schmidt, 'Untersuch. lib. d, Silur-Form. v. Ehst. N.-Livl. u. (Esel,' Archiv 

 f. Naturk. Liv-, Ehst- u. Kurlands, toI. ii (1861) p. 1 ; & Quart. Journ. Geol. 

 Soc. vol. xxxviii (1882) p. 514. 



* ' Eev. Ostbalt. Silur. Trilob.' pt. i, Mem. Acad. Imp. Sci. St. Petersb. ser. 7, 

 vol. XXX (1881) No. 1, p. 81. 



° Ibid. pt. iii, ser. 7, vol. xxsiii (1886) No. 8, p. 53. 



6 Monogr. Pala^ont. Soc. ' Brit. Trilob.' p. 192. 



' Freeh, ' Leth. Geogn.' pt. i, vol ii (1897) p. 91 footnote. 



8 Eichwald, ' Silur. Schichtensystem n Ehst.' 1840, pp. 170 & 171 ; von Huene, 

 Neues Jahrb. 1899, vol. i, p. 138 & pi. xii. 



