121 
Geological Relations of the East of Ireland. 
districts ; (see Plates 6 and 7, and PI. 14).* I have added views 
more in detail of the eastern range, leaving unnoticed no mountain 
of importance in that extensive tract ; (see Plates 8, 9, and 10) ; 
and in all these sketches it has been my chief endeavour to preserve 
a faithful and correct copy of the outlines presented by nature ; neg- 
lecting the subordinate considerations of ornament and picturesque 
effect, f 
§ 4. The different colours in the map mark the outline and 
extent of the principal formations, in ascertaining the boundaries 
of which no pains have been spared. The smaller subordinate for- 
mations could not be well introduced without producing confusion ; 
but in the text I have endeavoured to supply the deficiency. £ 
Form of the Surface . 
§ 5. In the landscape of Ireland, there is one very remarkable 
feature, which cannot fail to strike every observer. In traversing 
* In all these sections, I have adopted an equal scale for altitudes and distances ; so 
that they present a true profile of the country intersected. 
+ The stations, from which the views were taken, are marked on the map by asterisks 
and figures, corresponding with the numbers in the Plates ; viz. N° 1.* to N° 18.* 
J The bearings mentioned in the following pages refer to the Magnetic Meridian. It 
would appear that during the course of my observations, the variation of the needle has 
been partly progressive toward the west, and partly retrograde. I am indebted to the 
Rev. Mr. Hogg, Assistant Astronomer at the Observatory of Armagh, for the following 
recorded observations of the variation of the needle, made in the meridian of the observatory 
at that place . 
Year 1799, Dec. 27 . .Magnetic variation, 
north \Vest. . . 
. 27°. 40' 
1804, May 10.. „ 
55 
55 * * ’ 
.28 . 3l£ 
1805, May 14 . . „ 
55 
55 • * * 
.28 . 36 
1810, April 19 . . „ 
55 
55 * * * 
.29 . 00 
1814, March 25 . . „ 
55 
55 * * • 
.28 . 02£ 
1815, Feb. 9.. „ 
55 
55 **• 
.28 . 01 
1816, June 17 .. „ 
55 
55 * * * 
.$7 . 45f 
1818, March 17 . . „ 
55 
55 
.26 . 56 
Vol. V. 
Q 
