402 
REV. S. HAITGHTON ON THE JOINT-SYSTEMS OF IRELAND 
The precise bearings of these systems are — 
1. 
12 
8 W. of N. . 
. . . (C). 
2 # 
18 
5 E. of N. . 
. . . (C"; 
3. 
45 
0 E. of N. . 
. . . (A'). 
4. 
14 
0 N. of E. . 
. . . (A). 
5. 
1 
6 S. of E. . 
. . . « 
6. 
46 
26 W. of N. . 
. . . (O'). 
Of these systems of joints, 1 and 4, 3 and 6 are evidently conjugates, and neither 
system closely corresponds with those of Waterford and Donegal, although that named 
(A, C) comes within a few degrees of (A, C) of those localities. 
The Conjugate Joint-Systems of the Mourne and Newry Mountains are therefore as 
follows : — 
Table VIII. — Conjugate Joints of the Mourne and Newry Mountains. 
Designation. 
Magnetic bearing. 
True bearing*. 
Angle from 
East to North. 
A 
14 ON. ofE. 
39 40 N. of E. 
J 88 8 
C 
12 8 W. of N. 
37 48 W. of N. 
A' 
45 0 E. of N. 
19 20 E. of N. 
j 88 34 
C' 
46 26 W. of N. 
17 54 S. of E. 
In addition to ; the foregoing systems, which are evidently conjugate, we have the 
other systems, 2 and 5. 
Magnetic bearing. 
True bearing. 
System No. 2 (C"). 
System No. 5 (A 1 '). 
18 5 E. of N. 
1 6 S. of E. 
7 35 W. of N. 
24 34 N. of E. 
The accompanying diagram (fig. 5) exhibits the 
six systems of joints just described, with the num- 
ber of observations on which each is founded. 
A very remarkable system of trap dykes pene- 
trating the granite is exhibited in the railway cut- 
tings from the Goragh Wood station to Slieve Gul- 
lion, in the Newry Mountains. 
They are twenty-five in number, and are given in 
the following Table, numbered in order from Goragh 
Wood to Slieve Gullion. It appears evident from 
the Table that they are all reducible to four systems, 
two of which have directions closely corresponding 
with the joint-systems (C) and (C') already found. 
* The magnetic variation of the Mourne district was 25° 40 f W. 
