EARTHQUAKE OF CENTRAL .TAPAX, 1891. 0^3 



At. first, it points a little Avest of uortli as in llie Suzuka rido-e. then 

 tnrns to tlie nortli-oast at Il)uki. Afterwards the strike is due east- 

 west, then again it iniperceptiljly deflects towards tlie nortli-east, 

 retaining- the dip always on the left side (compare the profiles a—]), 

 c — d, n. XXVTir.). In fact, the course of the direction of strike 

 makes a sigmoi(hd cur^•e, from which it is eas}^ to concei\e tliat the 

 strata must liave sustained stress from ^.arious directions. 



Under such circumstances the axis of the s-uhHes must lune recei\ - 

 ed an excessi\e twisting stress, and we may rcasonahly expect that (hi- 

 ring the movement the heds of rocks must ha\e gi\en way to fracture 

 somewhere within the mountain, like the grou]> of tissures in a pane of 

 twisted glass, as experimented u])on l)y Da.uhrée.* There are. \ think, a 

 numher of such weak, ü'eoloii'ical lines in this reu'ion as Ihe eflect of 

 torsional movement ; the f )ur valleys, Tokuno-yama. Xeo, ^lugi, and 

 Itatori may he taken as (^f this class of dislocation, upon which the 

 atmospheric ao'cncies have exercised their denudinu" acti<^n durin"' the 

 course of ages in ])roducing the present deep ra\ines. As may be 

 clearly seen from the sketch given in IM. XXX., the courses of the 

 ahove-mentioned valleys are to]eral)ly regular, running parallel to each 

 other from north-west to south-east, and thus sti'et(hiiig from the 

 Kisogawa to the pro^■ince of Echizen, 



There seems to occur, besides tlie ;d)Ove mentioned parallel lines, 

 a numher of fissures at right angles to the pavachii^e^. These trans- 

 verse clefts, or to use Dauln-ée's word, (h'((clas('s. may he traced in the 

 zigzag run of the valleys. Tin' rallciis in flic Xortli of' Mino t]\ereforr 

 j)resnif xiich rnjuhivilioi in tlii'ir coitrxe, tlial llwij cttn In/ no mrans Ix' atln- 

 ]t)if((hJ(' to tlie rc'sult of mere crosirc (KjfNcics and tlicir origin must be 

 ascribed to deep-seated discontinuitii in tlie eartli's crust (P. XXX.). 



* Si/ntht'ti>fclit' Stiidimi :ur Espci-imcntdl-GeoJociic, p. 230. 



