CHINA, MONGOLIA, AND JAPAN. 79 



CHAPTEE IX. 1 



GEOLOGICAL ITINERARIES OF JOTJRNETSIN THE ISLAND OF 

 YESSO, IN NORTHERN JAPAN. 



The following notes were taken during journeys made in the service of the 

 Japanese Government, in the summer and autumn of 1862. As the very small 

 population of this northern island is composed almost entirely of fishermen, it is 

 confined to small villages scattered along the sea-shore. The only roads are those 

 connecting these hamlets, with the exception of rare bridle-paths penetrating the 

 interior. The mountains west and north of Volcano bay are covered with dense 

 forests and a denser undergrowth of a kind of bamboo, so close-set that the country 

 is impenetrable, excepting by wading in the beds of torrents. 



Thus the geologist is obliged to content himself chiefly with the sections exposed 

 on the sea-shore. 



Hakodade, the seat of the Viceroyalty of Yesso and Krafto,^ is at the foot of a 

 peak about 1,160 feet high, connected with the main island by a low, sandy neck. 



The rock that forms this island-like promontory is apparently a pluto-neptunian 

 product resulting from the metamorphism of trachytic tufas and conglomerate- 

 breccias. Where I examined it, it consisted of a fine-grained felspathic base, 

 containing — 



1st. Felspar in oblong crystals, from very small to one-third of an inch in length. 

 These were white, highly fractured, and frequently showed triclinic cleavage. 



2d. Quartz in pellucid grains, very irregularly distributed, in places absent, in 

 others equalling the felspar. 



3d. Hornblende in small prisms. 



4th. Magnetic iron in grains. 



The rock in this locality has somewhat the appearance of having been broken up 

 and partially refused, but more generally it shows signs of stratification, and I have 

 referred it to the extensive marine deposit formed out of the debris of volcanic 

 rocks.^ 



On the northern slope of the peak is a terrace of recent gravels raised 100 feet 

 or more above the bay. 



Between the hiUs of the main island and the sea there lies a plain the surface of 

 which slopes gently toward the water, where it terminates in places in high bluff's. 



* See Map, PI. 8. _ = Sagalin of the Russians. 



^ This is probably the rock described in Com. Perry's Japan Expedition, as granite with crystals 

 of turmaliue. 



