PHYSIOGRAPHY AND GEOLOGY OF TEE ISLANDS. 3 



apparently, come the northern islands of Shumshir and Paramushir, 

 which were undoubtedly once joined to Kamchatka. The most 

 recent are the smaller islands of Chirinkotan, Black Brothers, 

 Ushishir, Shirinki, Raikoke, and Ekarma, whilst the Mushir rocks, 

 Avos rocks, and Srednoi rocks, are probably islands just beginning 

 to make their appearance above the sea. 



In formulating this chronological sequence, the oldest islands 

 are considered to be those where there is a fair development of 

 sedimentary rocks — a rounded appearance which has gradually been 

 produced by subaerial denudation ; where volcanic activity is at a 

 minimum ; and where animals and plants are numerous. The 

 youngest members of the group, on the contrary, I regard as being 

 those where sedimentary rocks are absent — the mountains are sharp, 

 and not materially altered by denudation ; where volcanic activity 

 is at a maximum ; and where animals and plants are comparatively 

 scarce. 



The separation of the northern and southern islands from 

 Kamchatka and Yezo respectively, has been caused partly by 

 marine denudation, and partly perhaps by volcanic action, which, 

 building up huge mountain masses in one place, may have caused 

 a slow subsidence in others. 



There is abundant evidence that the Kurils are being pushed 

 up bodily above the sea, as well as being built up by ejectamenta 

 from volcanic vents. Judging from signs on the shores, and reports 

 of old navigators, we may conclude that this elevation is going on, 

 or has gone on, at a comparatively rapid rate. For instance, 

 quantities of driftwood, composed of big trees, are found up some 

 of the valleys some 30 or 40 feet above the height to which the 

 sea now rises. These heaps of old drift-stuff are partly buried 

 in the earth, and overg-rown with 2;rasses and coarse vefjetation. 

 On the south-east coast of Matau there are terraces and beach- 

 lines one above another, to perhaps 100 feet above the present 

 shore. In an old " China Sea Directory," I find the following in 

 a note on the Black Brothers (Brat Chirnoi) : "A reef, which 

 much resembles an artificial breakwater, extends a mile east from 

 its north point, and at its extremity is a long rock." 



At the present time this is part and parcel of the island, the 

 "reef" being a sandy neck of land some 50 feet high, and over- 

 grown with grass. Buried in the sand of this ridge, and even on 



