L 47 J 

 DENUDATION AT CULTRA, CO. DOWN. 



BY MARY K. ANDRKWS. 



( Concluded from page 1 8.) 



(Read before the Belfast Naturalists' Field Club, December 2otli, 1892.) 



Encroachments of the sea, similar to those described, have 

 taken place on the adjacent coast. Although no landmark 

 survives, it is estimated that within living memory the sea has 

 advanced more than 150 feet at Cooper's Bay, near Holy- 

 wood ; and Cooper's Green, once a favourite resort for rural 

 games, has now, with part of an inner adjoining field, com- 

 pletely disappeared. 



In confirmation of the foregoing notes it is interesting to 

 trace the changes recorded on successive maps of the Ordnance 

 Survey. On the six-inch map, surveyed and engraved in 

 1834, we find both the quarry at Cultra Point and the road 

 leading to Cultra Quay, while on the same map, revised in 

 1858 and engraved in i860, Cultra Point has a more smoothed 

 and rounded appearance, the quarr}^ is no longer marked, and 

 all traces of the road are gone. 



A comparison of successive Admiralty charts gives indica- 

 tions of somewhat similar interesting changes in Belfast I^ough. 

 In the chart for 1883, corrected up to 1891, the three- 

 fathom line (close to the end of the new cut recently opened 

 in continuation of the Victoria Channel) is more than 800 feet 

 nearer to Belfast than in the chart for 1841, corrected up to 

 1856. Within the same period the three-fathom line has also 

 approached more closely to Holywood and to Carrickfergus.' 



As geological structure has an important bearing on the 

 rate of erosion, it is necessary now to consider more closely 

 the nature of the strata near Cultra. The first rocks that crop 

 out on the beach a little north of Holy^vood belong to the 

 upper mottled sandstone of the Bunter formation ; further 

 east, near the low cliff in the illustration, we find reddish- 



iMr. Moore (Harbour Office, Belfast) kindly drew my attention to the 

 changes on the Ordnance maps, and to the approach of the three-fathom 

 line towards Belfast, indicated on successive Admiralty charts. This 

 latter observation has been confirmed by Mr. S. A. Stewart, F.B.S.E., 

 who further observed the general advance of the sea towards Holywood 

 and Carrickfergus. 



