io6 Guide to Belfast. 



The basalt dykes of the Mourne district have already been 

 referred to. The Geological Survey, in a note on their map 

 referring to the shore line south of Newcastle, records as 

 many as 140 dykes in \\ mile of coast. Many of these are 

 andesites, some are composite with later intrusions of eurite, 

 while two dykes of variolite half a mile north of Annalong, 

 and one dyke 2\ miles south of Annalong, have been 

 described in detail by Prof. Cole.^ 



BOTANY. 



By Henry Hanna, R. Lloyd Praeger, and 

 Rev. C. H. Waddell. 



FLOWERING PLANTS AND VASCULAR 

 CRYPTOGAMS. 



IN order that the character and distribution of the flora 

 may be understood, brief reference must be made to 

 the physical features of the area. Down and Antrim 

 occupy the north-eastern corner of Ireland, and form the 

 portion of that country nearest to Scotland. The district 

 is colder than Donegal, which adjoins on the north-west, 

 where the warm influence of the Atlantic is felt to a 

 marked degree. The waters of the North Channel and 

 Irish Sea, which wash the shores of Antrim and Down, 

 constitute the coldest marine area in Ireland. The extent 

 of the district is 2,148 square miles (Down, 957; Antrim, 

 1,191). The coast-line is extensive and varied. Rivers 

 and lakes are fairly represented. The district borders on 

 Lough Neagh, which brings some very rare plants into 

 the flora. Mountains are also well in evidence, the basaltic 

 plateau of Antrim providing extensive high grounds, though 

 no point rises above 1,817 feet; while in Down the granite 

 peaks of the Mourne Mountains form a salient feature, the 

 highest summit reaching 2,796 feet. Low-level peat-bogs 

 of considerable size occur in Antrim, but are now almost 

 cleared away in Down ; mountain bog is present in plenty. 



1 Sci. Proc. Roy. Dub. Society, vol. vii, N. S. , part 5. 

 Geolog. Mag., April, 1894. 



