284 Scientific Proceedings, Royal Dublin Society. 



on the basal beds of the different rock groups as they can be 

 seen in Ireland, with more special descriptions of the complicated 

 uneonformabilities. 



Eocene. 



Under the basalts or dolerytes of Ulster there are, in many 

 places, a thin conglomerate (flints in a white limey matrix) as- 

 sociated with shales, and in a few localities a bed of iron ore or 

 of lignyte. If the Tertiary rocks lie on the Trias or Ordovician 

 the conglomerate is conspicuous ; but if they lie on the white lime- 

 stone {Cretaceous) it is not so. 



Cretaceous and Jurassic. 



On account of the distinctive colours of the white limestone 

 and the red Trias rock the boundary between them is conspicuous ; 

 there is, however, no regular basal conglomerate ; but in places 

 there are lenticular patches of pebbly limestone containing " green- 

 sand " fossils. These seem to have accumulated in hollows. In 

 other places the Cretaceous rocks appear to graduate downwards 

 into the Jurassic ; no conglomerate occuring at the base of the 

 Jurassic. 



Trias and Permian. 



Between the Irish Trias and Permian there is no well-defined 

 boundary; nor between the supposed Permians and the Carbo- 

 niferous. 



The red beds of the Trias are distinguished from those of the 

 Carboniferous by their colour and lithological characters ; but the 

 supposed Permians have no distinctive characters except palaeonto- 

 logically. 



At Cultra, on Belfast Lough, the relations between the rocks 

 in which are found fossils of Permian types, and the associated 

 Triassic and Carboniferous rocks are very obscure. 



At Templereagh, Co. Tyrone, the dolomyte, in which were 

 found fossils of Permian type, seems to be a bed in the Trias. 



At the marble quarries, Armagh, the conglomerate and sand- 

 stones, said to be Permian, as far as they can be seen, might be 

 either the basal beds of the overlying Trias, or arenaceous members 

 of the underlying Carboniferous ; while the rocks in the Benburb 



