288 The American Geologist. November, i<m. 
ments with rare granite intrusions, whose folds originally striking in 
the Sinian direction (about W 30° S to E 30° N) were deformed by the 
southwardly migrated north zone to an arc convex to the N W 
and by internal compression has been soldered to the compressing 
range of the north zone along a long sharply drawn line. Where 
the latter experienced its sharp bending a nearly detached fragment of 
the south zone, the Akaishi range, was placed almost along the 
meridian side by side with the gneisses of the north zone, and now 
appears as if pressed in between the latter and the obstruction. In 
the north zone the inner (northern) portion suffered compression, the 
outer (southern) tension ; hence we find in the former a compact 
frame work but irregularity of strike, in the latter regular strike but 
lateral opening, fracturing to horsts and sunken areas into which the 
sea penetrates in' the form of bays which in part unite to form the 
interior sea. The granites appear to follow in part lines of fracture 
diriccted radially toward the outer zone. In the south zone on the 
other hand the outer (northern) portions of the arc were compressed, 
being crowded together upon a short line ; they close up the bays of 
the north zone and have brought about the narrowness of the entrances 
to them. The granites of the north zone end abruptly at the border 
line. 
3. The Equatorial main body is probably a continuation of the 
Tsinling-range, the Kuma-Kii range of an eastern member of the 
south Chinese mountain country. The arrangement of chains in the 
two ranges in South Japan corresponds to that which is the rule on 
the south side of the Tsinling. The Kuma-Kii range is a backwardly 
compressed arc soldered upon the lee side in the manner in which 
they there occur. A local deviation from the Chinese structure is 
conditioned by the dragged backward bending of the eastern part of 
both zones. 
4. The position of the Nagasaki triangle is not to be determined 
since the observations at hand are not sufficient. 
5. The fundamental structure of North Japan inclusive of Yezo, 
is characterized by the presence of three broad strongly folded rectili- 
near zones parallel to one another and striking in the direction N 
by W to S by E ; which from the names of their parts which appear 
as, independent mountain masses may be designated at the Hidake, 
Kitakami, and Abukuma zones. The latter consists of gneiss ; in the 
structure of the two first mentioned Paleozoic share with (probalily) 
Algonkian sediments. 
In the portion of North Japan lyiijg between the Abukuma zone 
and the great transverse fracture, the places where the underh'ing 
rocks come out fromi beneath the enveloping cover furnish at present 
no adequate support for a conclusion regarding the structure. In the 
hill countries of Kwanto, Aschio, Yamiso-Tsukuba, and Etschigo the 
basement consists of similarly folded Paleozoic schists and granites, 
to which in the Kwanto bill country the (Algonkian) Sombagawa 
stage is added. In the latter the strike is ^^" N W. in the others it 
