CHINA, MONGOLIA, AND JAPAN. 105 



hornblende-felspar rock. Here also the mean trend of the highly contorted beds 

 is between W. and N. 



The remaining older rocks of this part of the island belong to the Ichinowatari 

 series, and the argiUite beds containing the obscure vermiform fossil, so often men- 

 tioned. The Ichinowatari series are black and gray metamorphosed argUlacecus 

 rocks, associated with older or younger shale containing calamites of unknown age, 

 and with greenstone ; and they are characterized by metalliferous veins occurring 

 at least in both the argillaceous rocks and in the greenstone. 



The argillite beds we find at many points, throughout the region included in the 

 above itineraries, occurring in places either as a compact gray rock or as a shale, 

 while at Yurup it is metamorphosed to a compact black rock, tilted almost to per- 

 pendicularity. Between Tomarigawa, on the west coast, and Yurup, on Volcano 

 bay, it is found, excepting in one locality, to be the predominating rock wherever 

 the ravines have cut through to the bottom of the volcanic tufa-conglomerate strata. 

 The rocks in question have, in common with the Ichinowatari series, their argilla- 

 ceous character, their association with dykes and great masses of greenstone and 

 an identity of character in the metalliferous veins of the two localities, both as 

 regards the association of minerals in these and also as regards some pecrdiarities 

 in the condition of the greenstone near these veins. 



Finally we have seen, beyond Iwanai, near Ousubetz (north), a coal-bearing series 

 of more or less metamorphosed rocks, containing fossU Equiseta. 



We find, in the auriferous gravel of Kunnui, representatives of another class of 

 metamorphic rocks in the chloritic and micaceous schists, etc., which are probably 

 the source of the gold, and evidently exist in situ in the ridge between that place 

 and the Japan sea. 



The enumerated strata form, so far as my observation extended, the skeleton of 

 Southern Yesso. The local strike of the coal-bearing rocks of the Ousubetz (north) 

 is N. 30° E., being nearly at right angles to the N. W. trend of the peninsula on 

 which they occur. AU the other beds of the older rocks seem to have been aff'ected 

 chiefly by an uplift trending between N. and W., and to which that portion of the 

 island lying between Esau volcano and the mouth of the Toshibetz, on the west 

 coast, appears to owe its direction. 



We come now to the pluto-neptunian beds, consisting of great masses, more or 

 less stratified, of volcanic products in the form of tufas, sandstones, and coarser 

 conglomerates and breccias. 



This, by far the predominating formation, forms almost everywhere sloping plains 

 or terraces between the mountains and the sea-shore, and extends, at least in 

 places, entirely over the watersheds between Volcano bay and the Japan sea, form- 

 ing peaks, as the Obokodake, several thousand feet high. 



The petrographical character of these beds is very diiferent, not only in their 

 vertical, but also in their horizontal development. Along the west coast we find 

 thick beds of a white pumice-tufa associated with conglomerates made up of frag- 

 ments of a black compact rock, almost a pitchstone. Along the road from Tomari- 

 gawa to Volcano bay the lowest beds observed were of a more clayey pumiceous 

 tufa, and above these an immense development of a scoriaceous conglomerate-. 



14 July, 1866. 



