Vol. 52.] SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 655 



boundary runs along to Ben Voirlich by Cairn Celar and Ben Aber. 

 On several occasions, and more particularly between 1839 and 1852, 

 this region has been visited by several shocks in the valleys of Loch 

 Tay and Loch Earn, and above all at Comrie. The last-named 

 locality is the most unstable spot in the British Isles. 



3. Northern and Central England. 



^=89 kilom. (1833-1873). # 2 =44 kilom. 

 (65 localities and 159 shocks.) 



This region is limited by the two seas, and by three conventional 

 lines running from Irton to Muston, from Chester to Newport (Mon.), 

 from Newham to the Wash. The most unstable portions are 

 situated on the southern slope of the Welsh mountains and in the 

 middle part of the Severn Valley. 



4. English Coast of the Channel. 



S=99 kilom. (1848-1871). S 2 *=49 kilom. 

 (50 localities and 135 shocks.) 



This region is bounded on the north by a conventional line 

 running from Bristol to London. It is particularly unstable in the 

 Cornish and Dartmoor areas. From the seismic point of view the 

 Scilly Isles must be included in it. 



5. Caledonian Canal. 



£ 1 = 105 kilom. (1852-1871). #*=52 kilom. 

 (27 localities and 54 shocks.) 



This region is bounded by the heights of Monadh Liadh between 

 the Findhorn and the Spey, and by a conventional line drawn from 

 Loch Broom to the Moray Firth through Ben Wyvis. It extends 

 through the Western Isles as far south as Phadda. 



6. South-eastern Ireland. 



#,=132 kilom. (1852-1880). S* = 65 kilom. 

 (12 localities and 19 shocks.) 



Ireland, very stable as a whole, has only one area subject to 

 earthquakes, and that is the south-east. This is bounded by the sea 

 and by a conventional line drawn from Dublin to Kinsale through 

 Charleville. The portion most often shaken is Cork Harbour. 



7. Wales. 



^ = 138 kilom. (1839-1894). £*=68 kilom. 

 (16 localities and 29 shocks.) 



This region is bounded on the east by a conventional line drawn 

 from Chester to Newport (Mon.). As it possesses much the same 

 seismicity as South-eastern Ireland, the recorder is tempted to throw 

 the two regions into one — bridging over St. George's Channel. 



