240 Cambridge Philosophical Society. 



also at Carnsore, at the extreme south-east of Ireland. The granite 

 of the second type, which is a " Soda-granite," occurs at Rathdrum 

 and Oulart, and is distinguished from the former by a diminution of 

 silica and an increase of lime and soda. The third granite is peculiar, 

 and found only at Croghan Kinshela, near the gold-mines of Wick- 

 low. It consists of quartz, albite, and chlorite ; while the potash- 

 granites of the main chain consist of quartz, orthoclase, and marga- 

 rodite mica. 



The second part of the paper described the three granitic districts 

 of the north-east of Ireland, known as the Mourne, Carlingford, and 

 Newry granitic districts. 



The granite of the Mourne district consists of quartz, orthoclase, 

 albite, and a green mica, probably similar- to margarodite. 



The Carlingford granite is a potash-granite, in which hornblende 

 replaces mica. At the junction of this granite with the Carboni- 

 ferous Limestone of the neighbourhood, a remarkable change takes 

 place in the granite on penetrating the limestone in dykes. From 

 being originally a compound of quartz, orthoclase, and hornblende, 

 it is converted by the addition of lime into a compound of horn- 

 blende and anorthite, which latter mineral was noticed for the first 

 time as entering into the composition of British rocks. 



The Newry granites belong to the "soda-granite" type, and 

 resemble in many respects the secondary granites of the Wickiow 

 and Wexford districts. 



CAMBRIDGE PHILOSOPHICAL SOCIETY. 

 [Continued from vol. viii. p. 236.] 



Nov. 26, 1855. — A paper was read on the Earthquake in Switzer- 

 land in July last, by the Rev. O. Fisher. 



The 25th of July, 1855, on which the first and most severe shock 

 was felt, was a very wet' close day, and the little wind stirring came 

 from the S.W. 



In the Miinster Thai the earthquake began by a rumbling vibra- 

 tion like that caused by a carriage run under an archway, gradually 

 increased for about four seconds, and then suddenly ceased. The 

 oscillation seemed to be from E.S.E. to W.N.W., but would be 

 affected by the build of the house. 



In the church at Brienne two stones fell from the groining thirty 

 or forty feet into the organ pipes, to a point between 2 and 2^ feet 

 N. by E. of the point vertically beneath their first position ; and 

 allowing for the direction of the building, this would give the motion 

 of the earth about from N.E. to S.W. This wave may have been a 

 reflexion caused by the wave entering the Jura from the valley. 

 Another shock was felt at Brienne, at 10 a.m., on the 26th. 



The great shock was felt at Strasburg, slightly at Lyons in a 

 direction from E. to W. ; likewise at Chambery, Alessandria, and 

 Genoa. The account given by Plana in the Times does not seem 

 very intelligible, but as far as can be made out from the stopping of 

 the clocks, it gives the direction of the shock at Turin about 30° W. 

 of S. Chiavenna, the western shore of the Lake of Constance, and 



