60 Rev. J. G. Cumming on some of the more recent 



and removing the materials between the southern extremity of 

 the Isle of Man and a line extending from St David's Head 

 to Carnsore point. How vain the attempt to measure the time. 



That the destructive action was more rapid and intense from 

 the south than the north, appears from the fact, that whilst in 

 the north of the Isle of Man we have still remaining a tract of 

 about fifty square miles of pleistocene deposits, in the south 

 they are only preserved where resting upon the palaeozoic 

 rocks and at the head of deep bays. Why this should be the 

 case we can immediately perceive by contrasting the narrow 

 North Channel with the more open St George's Channel to the 

 south. 



One of the clearest proofs of the long-continued action 

 of the sea, at a higher relative level than at present of about 

 fifteen feet, is to be found in the Isle of Man along the south- 

 eastern, southern and south-western coasts, in the presence 

 of a series of water- worn caves, which are hardly reached by 

 the highest tides which now occur. No one can inspect these 

 coasts without observing the trace of extensive denudation 

 and destruction above the present sea-line. The Eye of the 

 Calf, the Burrough and Fistard Head, drilled completely 

 through ; deep caves in the palaeozoic rocks at Peel, Brada, 

 Perwick, Langness, Santon, Port Soderic ; deep indentations 

 in the drift-gravel wherever the sea wall of palaeozoic rocks 

 has been broken by a chasm, or descends below the line of 

 high water. This is instanced in the horse-shoe bays and 

 creeks of Port-Erin, Perwick, Port St Mary, Poolvash, Castle- 

 town, Derbyhaven, Coshnahawin, Saltric, Greenock, Douglas, 

 Growdale, Laxey, and Cornah — all embraced by hard por- 

 pheries, basalts, schists, and carboniferous limestone, which 

 are capped by the drift-gravel. 



In most instances, these bays and creeks present, at their 

 head or innermost recesses, perpendicular cliffs of the boulder- 

 clay and drift-gravel, not rising in every instance from the 

 present high water-mark, but from a level about fifteen feet 

 above it, and having a low raised beach of a more recent date 

 between them. 



Of this lower raised beach I have now to speak. At the 

 foot of certain slightly inland cliffs of the post-pleiocene period, 



