480 ' Proceedings of the Royal Irish Academy, 



A sponge doubtfully referred to Cliona, a few corals, and some 

 characteristic Graptolites, complete the list from the highly fossilife- 

 rous strata of Pomeroy and neighbourhood. 



The fossils described from Lisbellaw, Co. Fermanagh (Xo. 2 of the 

 Table), for the most part by General Portlock in the Eeport before 

 cited, number ten species only, four of them being Graptolites, which, 

 like those of Pomeroy, occur in dark-grey slates : thi'ee of these also 

 occur at Pomeroy, one only, Graptoliilim Sagittarius, up to the pre- 

 sent not having been recorded from that locality. The BivalTe shells, 

 Mytilus ductus and Cardiola semi-rugata, are exclusively confined to 

 Caradoc strata, the first-named species also occurring in precisely 

 similar rock at Pomeroy. The Cephalopod shell Poterioceras ajpp'oxi- 

 matum is likewise a typical Caradoc species, and exclusively confined 

 to that formation. 



The fossils discovered in the course of this investigation in rocks 

 previously described as Old Red Sandstone, at Casheldaff, X. W. of 

 Ballaghaderreen, Co. ]iIayo, !N". E. (Xo. 3 of Table}, are undoubted 

 Upper Silurian (as are other well-known fossils at Uggool, &c., in the 

 immediate neighbourhood to the S. W.), and of Upper Llandovery 

 types. Seven species were identified from the collection made at this 

 place on the occasion of our visit ; four of these have a geological 

 range from Caradoc or Bala to Upper Llandovery strata, two of them 

 continuing on into TVenlock strata. Of the remaining two species 

 one, Pentamerus ollonyus, is confined to Llandovery strata, the other, 

 Strichlandinia lirata, commencirLg in the Lower Llandovery, continues 

 on to the Wenlock ; both are, however, highly characteristic of Llan- 

 dovery strata. 



"We have included in the Table (Xos. 4, 5, 6, 7 and 8) certain 

 Lower Silurian fossil localities in the ^est Connaught district, coun- 

 ties of Mayo and Galway, and another (Xo. 9) from the Dingle district, 

 Co. Kerry, for comparison. Column Xo. 4 tabulates the fossils from 

 cliffs above Lcugh Bellawaum, Co. llayo, all being of Caradoc-Bala 

 types. Eleven species are enumerated fi'om this locality (Explanatory 

 Memoir of the Geological Survey to Sheets 83 and 84, p. 31), one 

 being of doubtful identification : seven of them are Brachiopods, one 

 Mollusca-Conehifera, two Xucleobranchiata, and one Cephalopod. 

 Three of these fossils, viz., Leptcena sericea, Orthis testudinaria, and 

 Seller ojahon hilobatus, range from Llandeilo to Llandovery strata ; 

 three, viz., Lingida ovata, Poramlonites intercedens, and Ctenodonta 

 transversa, are confined to Caradoc strata ; and three others, viz., 

 Orthis liforata, BelJeroplxon trilobatus, and Orthoceras ilex, range from 

 the Caradoc to "Wenlock and Ludlow strata ; all, therefore, are pre- 

 sent in strata of Caradoc or Bala age, although some of the species 

 commence in older formations, and continue on into newer. The 

 fossils collected from the S. E. side of Mweelrea Mountain, in the 

 county of Mayo (column Xo. 5), also indicate Caradoc strata: four 

 species only are enumerated, all of which likewise occur in the pre- 

 ceding locality. 



