l899-'00 TRANSACTIONS 133 



that some lands are rising, others falHng. Dr. Bell can de- 

 monstrate to you that the whole basin of even our Great I^akes is 

 tilting in such a way that, at a not distant epoch geologically 

 speaking, Niagara will cease to exist. 



The opinion of the Committee of the British Association for 

 t' e Advancement of Science for the investigation of Seismic 

 phenomena as voiced by Prof. Milne se ms to be that, while ad- 

 mitting a few earthquakes to be volcanic in their origin, the 

 majority of these disturbances result from the sudden fracturing 

 of the rocky crust under the influence of bending, and that the 

 after shocks which so frequently follow large earthquakes an- 

 nounce that the disturbed strata are gradually accommodating 

 themselves to their new positions. 



Prof. Milne says : ' ' Strong evidence of faulting being ac- 

 companied by earthquake motion is the fact that many large 

 quakes have been accompanied by faults which are visible at the 

 surface. The terrible shock which in 1891 laid waste hundreds 

 of square miles in central Japan seems to have been the immediate 

 result of a great fracture in the earth's crust which can be traced 

 for a distance of over sixty miles. The surface of the ground on 

 one side of this .line has fallen some twenty feet below the former 

 level. The main fault was accompanied by many minor disloca- 

 tions, horizontal displacements and even compression, so that a 

 river bed has been narrowed, while plots of ground which were 

 originally 48 feet in length have had this dimension reduced to 

 30 feet. In the Neo valley where the devastation was greatest, 

 whole tracts of rice fields on one side of the fault were suddenly 

 lowered relatively to those on the other side. The horizontal dis- 

 placements and vertical displacements which took place are 

 evident to every traveller throughout the district. A compression 

 of from I to 2 per cent across river beds had to be allowed for by 

 the engineers who reconstructed the fallen bridges, while the re- 

 measurement of land for government assessment showed that 

 certain areas had decreased in size. It is no doubt diflBcult for 

 those who live in districts where such convulsions as these are 

 unknown, to realize these statements, but when they are admitted 

 it is no longer difficult to suppose that such sudden changes could 

 have taken place without serious displacements in the mountains 

 rising from the area where they happened. A tract of country 



