RUSSEGGER — EARTHaUAKE AT SCHEMNITZ. 47 



later date than the granitites, which they cut through in the shape 

 of veins ; a circumstance differing from the facts observed in other 

 locahties. Along a line of considerable extent the granite is in con- 

 tact with the cretaceous limestones, which, for a hundred paces beyond 

 the line of junction, bear visible traces of the changes of structure 

 resulting from the contact of the granite ; they are saccharoid, fre- 

 quently dolomitic, and including granules of quartz and even some 

 mica; still, however, they show some vestiges of organic remains. 

 These facts lead to the conclusion, that the eruption of this granite 

 could not have been anterior to the cretaceous period. 



[Count M.] 



Notice of the Occurrence of an Earthquake at Schemnitz, 

 Hungary. By M. Russegger, Director of the Imp. Mining 

 Academy at Schemnitz. 



[Proceedings Imp. Acad. Sciences, Vienna, March 8, 1855.] 



An earthquake, the third within the space of nine months, occurred 

 at Schemnitz* on January 31, 1855. The shock was accompanied 

 by a noise hke the report of a cannon, and was felt in a vertical direc- 

 tion at 35 minutes past 1 o'clock, p.m. It was intense enough to 

 shake the walls of the houses. The maximum of its intensity coin- 

 cided with the centre of the town ; but (as in the previous shocks) it 

 was not followed by further shocks. 



The mines were visited immediately after the earthquake, and no 

 breach was found in them ; it was ascertained, however, that the 

 commotion had followed the direction of the principal vein (Spitaler 

 Hauptgang), and had reached below the greatest depths which the 

 workings had reached, increasing in intensity from above downwards. 

 In some places there were crevices in the solid rock and the walls of 

 the galleries ; but the timber remained unhurt. The cracking of the 

 rock was tremendous, and here and there the currents of air, arising 

 from the commotion, blew out the lamps of the miners, who, believing 

 that the whole mine was crumbling over their heads, were terribly 

 frightened. In some places fragments of rock were displaced and 

 injured the miners. 



The circle of commotion above-ground proved the shock to have 

 been central, and not to have followed the direction of a longitudinal 

 fissure. The form of this circle is remarkably coincident with the 

 outline of the inside of the mountain circle surrounding Schemnitz, 

 the outline being traced about the middle of the slope between the 

 bottom of the valley and the tops of the mountains. It has quite 

 the shape of a crater, on the north-east border of which rises the 

 basaltic cone of Mount Calvary. 



The depression in which the town of Schemnitz lies may with some 

 propriety be thought to exhibit a crater of elevation amidst a mass of 

 diorite and dioritic porphyry, diametrically traversed by the " Spitaler 

 Hauptgang,*' with a basaltic outburst (the only one in the immediate 

 vicinity) on its north-east border. 



* See the notice of the previous earthquakes at this place, aniea, p. 36. 



