123 
Geological Relations of the East of Ireland \ 
eastern flank, of the central part of this chain, presents a varied 
aspect ; being worn into deep glens and dells, which are lined with 
abrupt precipices, or occupied by lakes, from whence arise those 
narrow transverse vallies, whose general course toward the south- 
east is distinguished by the most beautiful and romantic scenery. 
The western flank, on the other hand, presents less variety: the 
glens and vallies, which exhibit fewer features of attraction, being 
more rounded and expanded. The rivers which arise in these, 
have a general tendency toward a north-west direction ; but, on both 
sides of the central range, the transverse vallies either merge into, 
or cut across more expanded, longitudinal vales, by which the 
central range is flanked, and beyond which arise offsets, or detached 
groups, and parallel ranges of lower hills. 
The central and northern part of this chain, was formerly in a 
great measure impassable ; presenting three openings only by which 
it could be traversed ; namely, those of Sally Gap, Wicklow Gap, 
and Glenmalur, and the first two were scarcely practicable even in 
summer : but an easy access is now obtained to every part of the 
mountains by means of the excellent military road, constructed by 
Government since the year 1798 ; which commences at Rathfarn- 
ham on the north, and terminates in Aughavanagh on the south. 
For the ascertained elevation of several of the principal points of 
this Eastern chain, I am indebted to Dr. Fitton, Mr. Richard 
Griffith, jun., Dr. Taylor, and Mr. Hugh Hamill, jun. ; the result 
of whose observations, together with my own, I have thrown into 
the following table.* 
* Almost all of these heights were calculated from a mean of barometric observations, 
made with Troughton’s improved mountain barometers; but a few W'ere determined by 
actual levelling. 
Q 2 
