292 Bonney — Glacial Action near Llandudno. 



the former place to Castell Diganwy Hotel cuts, on the northern 

 slope of the Diganwy hill, through a regular ' subalpine ' drift. 



(c) We come lastly to the shore section in Conway Bay. Going 

 from Llandudno, we pass a line of dunes of blown sand, and meet 

 with the clay at Tremlyd Point. This is the extremity of a deposit 

 which forms a slightly rising tract on the north-western face of the 

 Diganwy hills, and appears to be connected with that described 

 above, and to have once overspread the whole, or the greater part of, 

 the level Morfa Ehianedd. Here it forms cliffs about 30 feet in 

 greatest height, and extends along the shore for a distance of about 

 370 yards. It is capped by a sandy soil from 6 inches to 4 feet in 

 thickness, which was deposited, after the clay had been reduced by 

 denudation to its present form — a bank with gentle slopes north and 

 south. On each of these we find (1) a red marly clay, with but few 

 pebbles, which rises to the surface and disappears towards the middle 

 part of the cliff. The upper part of this, immediately under the surface 

 soil, is of a yellowish tinge, but the state of the cliffs prevented me 

 from ascertaining whether this change in colour indicated a distinct 

 deposit or not. Under this is (2) a bluish -brown clay, containing 

 many boulders of trap and metamorphic rocks from the neighbour- 

 hood of Penmaenmawr ; perhaps 25 feet in greatest thickness. 

 Many of these blocks contain 20 or 30 cubic feet, or even more ; and 

 scratches, apparently the result of ice-action, may be observed on some. 

 They are scattered over the shore for a considerable distance seawards. 

 Below this is (3) a bed of tenacious dark blue clay, full of small 

 pebbles of a dark slaty rock ; it only rises one or two feet above the 

 shore, but it may be traced for some distance below high water mark. 

 On the south slope the red clay in like manner replaces (2) and then 

 disappears under the sand ; in which, on both sides of the clay, are 

 seams of Mytilus edulis, beds of which occur at intervals along the 

 coast-section ; but, as these deposits are obviously of an age different 

 from that of the Glacial drifts, I abstain from entering into particulars 

 concerning them. A furlong or so beyond, the clay (1) rises from the 

 shore, and here also is capped by sand, containing beds of Mytilus edulia 

 and other shells ; and we again find it, after another interval of sand- 

 cliff, near the Castell Diganwy Hotel. I did not find shells in any 

 of these deposits. They seemed to have a general correspondence 

 with those bearing the same numbers in the Little Ormeshead 

 Section. 



To conclude. It would appear, from the above remarks that, after 

 the limestone hills of the district had acquired their leading forms 

 by upheaval and marine denudation, the whole district was de- 

 pressed. The summits of the low rocky islets thus formed became 

 capped with ice-fields, which, in places, descended in glaciers into 

 the sea. At times, very probably, they were united to the mainland 

 by pack or coast ice. The section on the Conway shore seems to 

 favour the idea that, at this period, there were oscillations of level, 

 during which the two lower beds were subjected to slight denuda- 

 tion. After the deposition of the uppermost bed of clay there must 

 have been considerable denudation, either from the action of the re- 



