54 BIN>IE: MESuZOIC rocks of the IJORTII-EAST coast of IRELAND. 
Here, in one narrow strip, we find the only representatives in 
Ireland of those Mesozoic deposits, which occupy such a broad 
expanse of country in England. Whether they were at one time 
deposited, and have been afterwards removed by denudation, or 
whether the geological history closed for Ireland in the carboniferous 
period, to be taken up again in the tertiary, must ever remain a 
matter of doubt. 
While the north coast rejoices in the presence of these peculiar 
deposits, it is also characterised by the absence of the carboniferous 
limestone, the deposit par excellence, of which the rock surface of 
Ireland is composed. The deposits before mentioned, are invaluable 
in proving the western extension of their English equivalents, and 
indicating by their texture and contents, that we are approaching 
the limits of the area of deposit. Within the confines of the limited 
area under consideration, there is one of those coal-fields, which 
are all too few for the manufacturing prosperity of Ireland, for, 
though the carboniferous limestone occurs in Ireland in such great 
force, the deposits which followed it, unless protected by some special 
agency, have been everywhere removed. The preservation of these 
exceptional deposits is in a great part due to the capping of the 
basalt, to which the distinctive chnracters of the scenery of the 
coast are due. 
The coast section of the plateau may be roughly described as 
occupying two sides of a triangle, starting from Belfast, it trends 
roughly N.N.W. as far as Bengore Head, a distance of 40 miles, 
where the line changes to W.S.W., and stretches in this direction for 
about 25 miles as far as Dungiven. The outline of the plateau is 
very irregular and broken, it is above the 500 feet line throughout 
its entire course, except where it is bruken by the river Bann and 
other smaller streams ; occassionally it rises into mountain peaks of 
1,500 feet. This altitude is no doubt owing to the basalt, which 
everywhere caps the older formations, thus protecting them. Barrois 
describes this plane as resembling a miniature Auvergne where the 
craters have been removed ; he describes the flow as rectang-ular, the 
two adjacent sides which we are following, being those from Lough 
Foyle to Bengore Head, and from Bengore Head to Belfast. 
