DEPOSITS AND ELEVATION. 7 



more or less loaded with limestone detritus of all sizes, 

 from blocks containing many cubic yards of stone down- 

 wards. These detached rocks crowd the sward and steeper 

 inclines and add much to the picturesqueness of the north 

 face and its romantic walk. They are often sharply angu- 

 lar, but occasionally are weathered or waterworn into 

 rounded boulders. In the flatter hollows or the lower 

 plains of the central depression there is under the sward 

 a certain amount of humus of no great depth. The Head 

 is connected with the mainland of Denbighshire by the 

 Llandudno isthmus, widening eastward to the foot of 

 the range of limestone hills which ends northwards in 

 Little Orme's Head. Southwards the isthmus, embracing 

 two or three piles of igneous and altered Silurian formation, 

 passes towards Conway and its eastern estuary. The river 

 Conway separates it from unaltered and altered Silurian 

 beds and the great Trap ridge of Conway Mountain. The 

 Conway estuary on the south-west, and the tides of the 

 Menai Straits, the Irish Sea, and Llandudno Bay on the 

 west, north, and east, and rain and frost above high water- 

 mark, are continuing in this our own day the processes 

 which in the course of ages have shaped the outline and the 

 profiles of the head to what we now see. 



Its general superficial outline may be assumed to be 

 due to prolonged subaerial and later marine erosion, pos- 

 sibly aided at some period of the process by the friction of 

 land or floating ice — but in the last instance, and ever since 

 its first emergence, to a long- continued and extremely tran- 

 quil elevation and concurrent secular subaerial degrada- 

 tion and deposit, under the never-ceasing alternations of 

 wind and rain, heat and cold, and vegetation. 



The isthmus appears to consist of ancient sea-bottom, 

 gradually raised, and denuded in the process by currents or 

 tide-wash, and then augmented by beach-accumulation and 

 blown sand, each apparently derived from the eastern bay. 



