312 NOTE ON RECENT EARTHQUAKE IN CAPE BRETON. McIN.TOSH. 



rather to be sought for in the sedimentary strata that overlie 

 the igneous rocks. Limestones and gypsum are plentiful in 

 these. The falling in of the roof of a subterranean cavern 

 formed by the action of percolating water on the limestones and 

 gypsum would account for the shock. It is highly probable 

 that such a cave-in, or a fault produced by some readjustment 

 of the carboniferous strata, was the cause of the recent earth- 

 quake shock. 



