Vol. 58. ] CARLISLE AND INVERNESS EARTHQUAKES. 397 
EXPLANATION OF PLATES XI & XII. 
Puate XI. 
Map showing the isoseismals 4, 5, 6, 7, & 8 of the principal Inverness 
earthquake, on the scale of 30 miles to the inch. 
Puate XII. 
Map illustrating the area affected by the accessory shocks of the Inverness 
earthquake, on the scale of 6 miles to the inch. 
DisctssIon (ON THE TWO FOREGOING PAPERS), 
Prof. Jupp said that everyone must be struck by the conjunction 
of two earthquakes with such dissimilar features. The move- 
ment in Cumberland was probably not of long continuance nor 
originating from a very old disturbance; moreover, it seemed to 
take place along a fault of which there was no evidence at the 
surface. In the Loch-Ness district, however, the fault-line was 
plainly apparent at the surface, and there was evidence that the 
recent disturbance was the continuation of movements that have 
been going on for ages. He expressed his gratitude to the Author 
for the care that he had taken in bringing the facts together. 
The Rev. Epwin Hitz expressed admiration of the Author’s work. 
Referring to the Carlisle paper, he asked whether the words ‘in the 
surface-rocks there is no sign’ of such a fault, meant that these 
rocks were not faulted. If so, did this imply that stress had been 
accumulating through geological periods, or that a cause of stress 
had after such periods been renewed? ‘The latter was easier to 
imagine. He had heard that a recent earthquake in New Zealand ~ 
had been followed by frequent movements through many weeks, 
and expressed a hope that there had been some worker on the spot 
as enthusiastic.as the Author. 
"Mr. Grusoy cited instances from North Staffordshire and N otting- 
hamshire of great faults affecting the Coal-Measures, now ‘yume 
beneath the undisturbed Trias. Such faults might be revealed by 
earthquakes. 
The Presipent referred to the great geological importance of the 
Author’s researches into the phenomena and distribution of British 
earthquakes in general; and pointed out how greatly he had 
enlarged our previous ideas as to their frequency in what we 
very naturally regard as a comparatively stable region. The 
painstaking manner in which he collected his materials, and the 
cautious way in which he drew his conclusions, inspired one with 
confidence in his results. He was especially to be congratulated 
on the advance that he had made in our knowledge of the 
subject as a whele, by his demonstration that most, if not all, 
the British earthquakes are due to slipping movements along fault- 
planes; by the discovery of twin earthquakes, and of the fact that 
the trends of the various earthquake-sliplines are more or less 
coincident with the four recognizable trends of crust-folding in the 
