0K(M.(K;I( AL NOTES. 



By (teoffkey Stkai), B. A.. L\ K. 



'T T may l>e of interest, after seeing so much in the daily ))a])ers 

 ^ of the last few weeks about tlie terrible disasters that have 

 befallen our fellow men near Naples, Italy, and in San 

 Franeisco, to consider what movements of the Earth's crust may 

 have occurred or be occurring in our own Provinces, and what 

 evidences there are of volcanic action near at home. 



Fortunately the traces we have of the latter phenomena belong 

 to far distant periods of time. The regions of volcanic; activity 

 seem to shift from one part of the world to the other, in the 

 different ages, and seem to be connected with and follow periods 

 of great deposit and rock building. 



Probably to some extent the course of events may be as follows: — 

 The Earth, in giving up its heat, contracts, and the surface sinks 

 over a certain area. This area becomes gradually a basin to which 

 the drainage of the surrounding tracts flows, carrying sediment 

 — sand, mud and even large stones. This sinking and de])osit 

 may go on for ages, until a great thickness of soft materials has 

 formed. 



The original hardened surface of the Earth is then in this area 

 bowl-shaped, or in the fornj of an mverted arch. Its sides are 

 easily bent by i)ressure from the surrounding crust, and its 

 centre is probably fractured or rendered hot and plastic l)y the 

 weight of the de])Osits. 



Thus such an area of settlement and deposit becomes a weak 

 spot on the Eprth's crust, and is not able to resist the i)ressure 

 on its sides. 



The soft beds of sediment are gradually hardened by the pres- 

 sure, and at the same time contorted and folded, and most 

 probably are in part raised far above the general level. 



This movement and pressure generate great heat, sufficient 

 probably to melt parts of the lower strata. Fissures and cracks 

 appear, especially near tiie centre of the basin, where the folding 



