KiNAHAN AND Baily — Report on Rochs, 8fc. 479 



PAET II. 



Pal^ontologicai !N'otes. By "W. H. Bailt, F.G.S. 



The following Table includes a complete list of recorded species 

 from the localities mentioned at the head of each column : to these 

 are added some others, the result of our visit to the districts we pro- 

 posed to investigate. 



The first column (iS'o. 1) is that of the Pomeroy district, Co. Tyrone, 

 celebrated for the beauty and variety of its fossils. The large number 

 of 1 1 1 species are included in this list from that comparatively small 

 area of strata. Amongst them the Trilobites, an extinct order of Crus- 

 tacea, number 27 species; Brachiopoda, 20 species; Mollusca-Conchifera, 

 14 species ; Gasteropoda, 10 species; Pteropoda, 5 species; and Cepha- 

 lopoda, 15 species : all these are Lower Silurian fossils of Caradoc-Bala 

 types. The majority are described and figured in Portlock's Eeport 

 on the Geology of Londonderry, Tyrone, &c. The Trilobites include 

 species, some of which, as Cyhele rugosa, Remopleurides Colhii, Fhacops 

 Brongniartii, P. tnmcato-caudatus, Trinucleus concentricus, and T. seti- 

 cornis, being identical with those of Caradoc or Bala age from England 

 and Wales : others, such as Sarpes Borani, S. Flanagani, Ampyx 

 rostratiis, Asaphus gigas, A. radiatus, A. rectifrons, IllcBnus Portlochii, 

 Staurocephalus gloliceps, Stygina latifrons, andPronteus MihernicKs, are 

 exclusively Irish species. The Brachiopoda are next in importance 

 to the Trilobites in respect to the number of forms ; amongst them, 

 Lingula Irevis, Orthis fallax, and 0. intercostata, are the only species 

 at present known to be exclusively Irish ; the others, although some 

 of them, such as Discina oblongata, Orthis liforata, 0. crispa, 0. por- 

 cata, 8troplionema corrugatella, S. expansa, S. grandis, are eminently 

 characteristic of Irish strata, also occur in England and "Wales, and 

 some of them in Scotland. Bivalve and univalve lloUuscan shells 

 (Conchifera and Gasteropoda) are not nnfrequent in these grey schists. 

 Amongst the former, Kucula-like shells, Ctenodonta, are plentiful, as 

 many as six species being enumerated ; it is very possible, however, 

 that some of them may prove to be merely variations of form ; Modio- 

 lopsis and Ambonychia are also frequent. Of the Gasteropoda, or uni- 

 valve shells, Euomphalus and Murchisonia are the most frequent. The 

 IS'ueleobranchiata include three species of Bellerophon, and the Ptero- 

 poda two species of Conularia, the remarkable spirally- coiled Eccu- 

 liomphalus Bucklandi, and two species of Theca. Shells of Cephalopoda 

 are frequent, particularly Orthoceras, which is represented by twelve 

 species, four of which — 0. Ireviconicum, 0. elongato-cinctum, 0. per- 

 annulatum, and 0. Pomeroense, are confined to this district ; the cui'ved 

 Cyrtoceras inmqidseptum is exclusively an Irish fossil, although it has 

 also been found in beds of similar Caradoc age at Tramore Bay, 

 Co. Waterford. 



