2i6 The American Geologist. October, i904. 
with time, our primitive notion comes to be largely modified; and, at 
present, we can say positively that north and south Japan differ in that 
the prevaiHng direction of the south is greatly influenced by the folding 
axes while that of the north is by the meridional rupttiral lines. 
The external side of North Japan, in contrast to the regular suc- 
cession of geological formations of the south, consists of three tectonic 
blocks, — that of the Paleozoic Chichibu (Kwanto), of the Archaean 
Abukuma, and of the Mesozoic .and Paleozoic Kitakami ; and these are 
the gigantic crnstal clods that bound the Pacific sea-board, each form- 
ing a geological unit, and an independent upland region. The geo- 
graphical back-bone and the main water-shed of north Japan, lie, how- 
ever, westwards of the discontinuous ectoperipheral zone, and is main- 
ly built up of the quartz-bearing tuffytes of a Tertiary age. These 
remarkably constant pyroclastics constitute the foundation, through 
which the various andesitic lavas have welled out in post-Tertiary 
times in a nearly meridional direction, creating a long series of over- 
towering mighty cones. 
If we were asked what is the mother-rock which supplied the ma- 
terial to the tuffytes, we can onlj^ say that it is the rhyolyte which had 
been poured out at the bottom of the Neogene sea, and whose deriva- 
tives, the tuffytes, had been deposited in so vast an extent as to serve 
for the foundation of nearly the whole of North Japan, excepting the 
three uplands, already mentioned." 
Below I translate with few and brief omissions the text of v. 
Richtofen's study of Japan above cited. 
* * * The study of the latter island (Yezo) has lent a new aspect 
to the picture. For it has shown that from its northernmost point 
certain lines having their origin in the geological structure stretch 
out southeastwards into the sea through a southwardly directed di- 
vergence, without appearing again in the following islands. The west- 
ermost line of Sachalin is continued in the Hidaka or axial chain of 
Yezo, and runs likewise into the sea without recognizable continuation. 
We limit ourselves here to the three large islands of Japan proper; 
Hondu (or Honshu), Shikoku and Kiusiu, with their small insular be- 
longings, and the western section of Yezo with its numerous members. 
I, myself, have in the year 1871, when the permission to travel was 
rarely conferred and wns difficult to obtain, visited the environs of 
Fuji-yama and Fusi-yama itself, made a journey along the Nakasendo 
straits with certain side excursions, and traveled over the island of 
Kiusiu. At that time the geology of the land was completely unknown. 
The knowledge derived from these journeys, of the structure of the 
formations concerned, and many of the more important stratigraphic 
relations, has become of use in understanding the latter representations 
and the geological map. 
By the comparison of the Japanese islands with the continental 
regions lying within the same longitudes; (Korea. Liao-tung. and north 
China) the striking difference makes itself apparent that upon the con- 
tinent the complex of Paleozoic formations has a plateau-like posi- 
