122 A. C. RAMSAY ON THE ISLAND OF ANGLESEY. 



ferous strata of that region had heen pounded and crushed, so as 

 greatly to facilitate their removal by denuding agencies. He in- 

 quired whether Prof. Ramsay could define more closely the period 

 of the upheaval near the Menai Straits. 



Mr. Henry Woodward remarked that since the Glacial period a 

 considerable subsidence of Anglesey had taken place, and instanced, 

 in support of this view, the finding of a jaw of Elephas primigenius 

 associated with old forests at a great depth during the excavations 

 for the enlargement of Holyhead Harbour. He thought that ice 

 from Cumberland would suffice for the glaciation of the surface of 

 Anglesey without going so far as the North Pole. 



Mr. Fordham inquired why we should go to Cumberland for ice 

 when Snowdon was so near. If there were ever a polar ice-sheet, 

 the mountains of Cumberland and Wales, he thought, were not 

 worth mentioning. He inquired whether there were any erratic 

 blocks in Anglesey which might indicate the source of the ice by 

 which it was glaciated, and also whether the Great Orme's Head 

 was striated. He thought there was some reference to the Straits 

 having been much shallower than at present within historic times. 



Mr. Drew confirmed Prof Ramsay's views. The Straits are now 

 margined by cliffs, owing probably to erosion subsequent to their 

 formation. 



Mr. Jordan remarked that faults, as a rule, do not affect the 

 surface. 



The President (Mr. Evans) remarked that he understood Prof. 

 Ramsay to maintain that the general features of the country were 

 preexistent to the Glacial period, but that where there were softer 

 rocks the ice cut through them, the hollows thus formed being after- 

 wards often filled up and reexcavated by subaerial denudation. 



The Author, in reply, stated that at the close of the Carboniferous 

 period Anglesey was covered with Carboniferous strata, and that, 

 although faults did occur in places, letting down portions of these 

 rocks, these had nothing to do with the production of the Menai 

 valley. The Millstone Grit and Coal-measures, not less than 1500 feet 

 thick, originally lay over the Carboniferous Limestone of Menai Straits 

 when the faults were produced. The ice came from the north-east 

 and not from Wales ; and the striations pointed directly towards 

 Cumberland. The Great Orme's Head could hardly show any striae, 

 as its surface had been greatly affected by weathering. Many erratics 

 occur near Beaumaris which are similar to the rocks of Cumberland or 

 Galloway, and which may perhaps be identified with them. 



