QUATERNAEY DEPOSITS OF BRITISH ISLES BROOKS. 333 



necting former islands with the mainhind; the neck of the Hill of 

 Howth is a notable example. Reference is made to these raised 

 beaches in many of the Geological Survey Memoirs dealing with 

 maritime districts. The 25-foot beach attains its greatest height 

 at Malin Head, where it is about 33 feet above high-water mark; 

 north of Londonderry it stands at 32 feet, in Lough Foyle and along 

 the coast of Deri-y and Antrim about 25 feet. In sheets 20, 21, 28, 

 and 29 the maximum height attained seems to be 15 to 20 feet, includ- 

 ing the M ell-known bed at Larne. At about this height well-marked, 

 shelly, raised beaches extend down the east coast; at Dublin, the level 

 is 10 to 15 feet, and in the Counties of Wicklow and Wexford it 

 ranges from 12 to 6 feet, very conspicuous in places. 



On the south coast we have no mention of a postglacial raised 

 beach except at Cork, where in the quieter channels a grass-grown 

 flat backed by an old cliff a few feet above present high-water mark 

 may represent this feature. On the flat occur kitchen middens. The 

 only points on the west coast where any vestige of a raised beach is 

 seen are Drumcliff Bay, near Carney, County Sligo, where a beach- 

 like bed 6 to 7 feet above high-water mark contains remains of 

 oysters, clams, and periwinkles (Memoir sheets 42 and 43, 1885), and 

 near Sligo (Memoir sheet 55) , where a " silty bed containing cockles " 

 lies appreciably above high-water mark; and the middle island of 

 Aran, where a shell-bearing beach is recorded by Kinahan, and at 

 the mouth of the Kenmare River, in County Kerry, where there is 

 a thin bed of oysters and other shells just above high-water mark 

 (Memoir sheets 182, 183, and 190). There is thus a striking decrease 

 in the height of this beach from northeast to southwest. 



The molluscan fauna of the 25-foot beach of northeast Ireland has 

 been studied by Mr. Lloyd Praeger (1896) ; he finds a complete ab- 

 sence of arctic species, and only three of northern type, while nine 

 species are of marked southern type. In the present seas of the dis- 

 trict the numbers are four northern and three southern. This indi- 

 cates that the climate was somewhat warmer than the present, instead 

 of being colder, as it was when the higher beaches were formed. 



Below the level of the 25-foot beach in northeast Ireland are 

 numerous other beach terraces extending down to high-water mark. 

 Among these a 15-foot beach is often distinguished; in fauna and 

 general characters it is not very different from the 25-foot beach and 

 is probably very little later, Kinahan (1878) supposed it to be 

 separated from the latter by a 30 to 40 foot elevation, and referred 

 the Kilroot gravels to the 15-foot beach, since they contain imple- 

 ments considered by Mr. Du Noyer as younger than those from 

 Magheramorne and Larne. In the river valleys the 25-foot beach 

 is often continued as a gravel terrace 25 feet above the present level 

 of the water, and evidently due to the same submergence. By anal- 



