198 '^- ivOTö. 



That geotectonic liiie is :i]so approxiiiiatelv tlie hoiindary of the 

 vegetation of the nortJi snhtropical zone,^ or the zone of Piiius Tlmnhergli, 

 and 'rcrmlroemiaccœ are rarely found to the north of that Jiniit. 

 Thus, from various sides, geologically, historicallv, and olimaticallv, as 

 well as phytogeographically, this line serve.; as the l)Oundarv for the 

 great natural division of the Empire. 



North dajian hegins from the east side ;)f the Hakoné inonntains, 

 running straightforward«, in almost meridional direction, towards Hok- 

 kaido ; and along its Pacific side is to be seen a relic of a once 

 gigantic Arclisean realm, though disturbed in various ways. Be- 

 tween this i)re-pala3(3zoic band and the backbone of the island, longi- 

 tudinal and radial valleys have been scooped out, those of the Abu- 

 kujui-gawa. Tone gawa, Naka-gawa, and, lastly, of the Kuji-gawa. 



The south end of the above-mentioried Arclifean belt lias been 

 briefly sketched out l^y the ])resent writer in one of his former paj^ers,- 

 On tJic so-called CrijstaUinc Scliists of ChicJiibu ; the present one is an 

 instalment of the results accruing from several occasional trips, 

 since ma.de in the nortiiern prolongation of the same belt, i. r., tlie 

 Abukuma I'lateau. 



II. The Abukuma Plateau. 



IVoceeding northwju-ds from Mito, in the province of Hitachi, 

 once the resident-town of the princes of the same na,me, through Ha-ma- 

 kaidö or the coast-road of Iwaki, to the mouth of the Abukuma, w^e 

 there get a tolerably good view of the physical features of the 

 plateau. The scenery is simple, but grand ; the thickly wooded, pre- 

 cipitous escarpment faces the sea, with an approximately meridional 



1 M. Fesca, Beiträge zur Kenutniss der japanischen Landwirthschait, Allgemeiner Theil, 

 Karte der Vegetationsgebiete, Tokyo, 1890. 



2 This Journal, Vol. II., p. 79. 



