284 Proceedings of the Roi/al Irish Academi/. 



section is laid bare across the Dingle and Smerwick beds, both having 

 exactly the same Hthological characters, and regular southerly dips. Admitting 

 for a moment that the " Dingle Beds " do lie conformably on the Wenlock and 

 Ludlow rocks on the south, we should, of necessity, expect to find the Wenlock 

 and Ludlow strata on the north-east of Smerwick Harbour, between the 

 " Smerwick Beds " and "Dingle Beds." But no such rocks occur there, although 

 the thickness of the Wenlock and Ludlow, immediately to the south-west, is at 

 least 4,000 feet. The absence of the fossLUferous Silurian rocks here is 

 conclusive that the Smerwick and Dingle rocks are of the same age. 



The accompanying map (Plate XX.) shows, in a general way, the geology 

 of the Dingle peninsula. The boundary-lines of the Silurian and Old Eed 

 Sandstone are copied from the Geological Survey map. 



The section (Plate XXI.) shows, in a diagrammatic way, my reading of the 

 " Dingle Bed " question, in which it is for the first time put forward that the 

 " Dingle Beds " are the lower strata of the Upper Silurian series, probably 

 Llandovery. 



