Demidation at Ciiltra, Co. Dcncu. 40 



drawn away in large quantities as the tide el^bs, with tlie sand 

 and gravel of the bay." 



As very complete sections of Triassic strata are laid open in 

 Cheshire, it may be interesting before concluding to give an 

 example of the denudation to which they have been subjected. 



Mr. Woodcock informs me that at Hilbre Island, off the 

 north-west side of Cheshire, the formation exposed belongs to 

 the pebble beds of the Bunter series. Although at low water 

 easily approached from the mainland, Hilbre Island is at high 

 tide exposed to the full sweep of the waves. The result of the 

 action of the sea, aided by subaerial agents, such as sand- 

 charged wind, rain, spray, frost, and heat, has been to wear 

 down and wear back the land area, so that what was originally 

 a tongue of land stretching out into the sea is now three 

 islets. The process of denudation which has separated them 

 is at present distinctly operating upon the larger one, so that 

 at its south-east end a small portion has become totally 

 detached and this at high water forms another islet smaller 

 than the rest. 



I have only to add that much of the low cliff around Cultra 

 Bay is now concealed behind a strong sea wall, which, for 

 years to come, may offer effectual resistance to the inroads of 

 the waves. We may regret the picturesqueness it has marred, 

 the interesting spots now covered over, but we cannot close 

 our eyes to the necessity of preserving the land, nor to the 

 important bearing which the alteration of a coast-line may 

 have on the maintenance of a harbour. 



We have glanced at the apparent destruction of a small land 

 surface, we have seen its materials loosened, disintegrated, 

 falling a prey to the energy of waves and currents, but the 

 destruction is not ultimate. The sea not only grinds down, 

 it sorts and arranges the fragments and lays them down to 

 form new strata on its floor. Consolidation and ultimate 

 upheaval will surely follow, but the processes by which these 

 stages in the earth's architecture are effected remain obscure. 

 We await further light, satisfied if we have illustrated one 

 small link in that marvellous cycle of order and change 

 traceable throughout the whole Geological Record. 



1 1 am indebted to Mr. James Shannon, boatman, Holywood, for the 

 above information. He has further observed that the water in CuUra Bay 

 has, within his own memory, become decidedly deeper. 



