Vol. 65.] KOCKS OF THE TOUEMAKEADY DISTEICT. 153 





Plate VI. 







la. 



Ittcenus weaveri, sp.now Head-shield, 



seen from above. 



X3. 



16. 



Do. Head-shield, 



seen from the front. 



x3. 



1c. 



Do. Head-shield, 



seen from the side. 



X3. 



2. 



Do. Pygidium. 



X2. 





3*. 



Do. Free cheek. 



X 3. 





Fig. 



4. Pliomcra nW.fischcri, Eichwald. Pygidium. x2|. 



5. Pliamera aff. harrcmdei (Billings). Pygidium. x2. 



6. Cybele connemarica, sp. nov. Pygidium. x4. 



7. Do. Pygidium: impression. x4. 



8. Acidaspis (?) sp. Pygidium. x3. 



9. Apatocephalus (?) sp. Free cheek. X 2. 



10. Telephus hibernicus, sp. nov. Head-shield, x4. 



11. Do. Head-shield. X4. 



12. Symphysurus (?) sp. Imperfect head-shield. Xl£. 

 13 a. Acrolreta (?) hibernica, sp. nov. Pedicle-valve, x 3. 



13 6. Do. Pedicle-valve: side view. x3. 

 13c. Do. Pedicle-valve: ornamentation. XlO. 



14 a. Sireptis affinis, sp. nov. Impression of exterior of pedicle-valve. X3. 

 14 6. Do. Cast of interior of same valve. X3. 



Discussion. 



Prof. Watts congratulated the Authors in having made a definite 

 correlation between the rocks of this area and of British areas, 

 such as Girvan, in which the succession was well known. He was 

 also pleased to find that it might now he regarded as settled, that 

 the contemporaneous igneous rocks of this area were not of Silurian 

 age. 



Mr. H. H. Thomas, in view of the great thickness of strata between 

 the Tetragraptus-Heds and the Llandeilo Flags in Wales, suggested 

 the possibility of the lowest rhyolite being of earlier date than the 

 Llandeilo, especially as there was evidence of volcanic activity in 

 Wales at a low horizon in the Didymograptus-bifidus Beds. 



Mr. B. Smith, commenting upon the resemblance between the 

 Tourmakeady Beds and those of the same age in the Girvan district, 

 mentioned by Prof. Watts, pointed out that the rocks of the 

 Pomeroy Inlier in County Tyrone (the Desertcreat Group, of 

 Upper Ordovician age), which lay almost upon the same line 

 of strike, had their nearest equivalents in the Drummuck Beds of 

 Girvan. A link between the Ordovician fauna of Ireland and 

 of parts of Europe was also furnished by the highest Ashgillian 

 Beds (Tirnaskea), in which a trilobitic fauna was associated with a 

 graptolitic one. For example, the recurrent trilobite of Barrande's 

 ' colonies,' JEglina rediviva, recognized here for the first time in 

 Ireland, was found together with Dicellograptus anceps, the highest 

 zone-fossil of the Southern Uplands. 



Mr. 0. T. Jones remarked that a number of complicated events 

 appeared to have been crowded into a comparatively limited space 

 of time, if the earliest volcanic activity were referred to the Llandeilo 

 Period. This phase was presumably followed by the deposition and 

 consolidation of the limestone, which was disrupted together with 

 the felsite to form the felsite-breccia ; yet the fossils of the higher 

 beds still indicated an horizon of Llandeilo-Flag age. It seemed 

 to the speaker that the conglomerate-beds bounding the area on 



