JIMBj : GEOLOGY OF JAPANESE SAKHALIN. 2 1 



at present not much to discuss. The thick vegetation, hiding all the inner structures 

 of land, is one never seen in South Manchuria, where natural geological profiles are 

 exposed in many places to travellers, who vainly seek for the shade of trees. In 

 Sakhalin, the principal fault-lines and axes of folding are not yet known. Clefts 

 in submarine shelves, found at Rakumaka, IMauka, Ohotomari. Asannai, Okö, 

 and [Nloiretomari, have already been spoken about. They are, according to 

 KaTAVAMA. probably ditch-like depressions along prewiiling fault lines of local 

 importance, parallel to which rivers run. 



Generally speaking, the mountains of Sakhalin are characterized by gently 

 sloping, open valleys, without many high precipices on the side of rivers. Water- 

 falls are seldom met with, though rapids and gorges are found. Exceptions to this 

 are found in the region of older rocks, especially in the Northeastern Mountain- 

 land. One indeed wonders, when he first looks at the almost dried-up beds of 

 man}' rivers, running across the highway leading from Korsakoff to Dubki, and 

 then proceeds only a few kilometers up those rivers to find a wild flow of abundant 

 cold water even in summer. The rugged sceneries on the eastern part of the 

 50th. Parallel is a more remarkable one. Naked peaks of rock, horns of 

 quartzite, stone-deserts on mountain-slopes, torrents descending almost vertical cliffs 

 more than 100 meters high, many gorges and rapids :- all these surprise observers 

 coming new from the flat plateau-lands round Korsakoff. In the region of younger 

 rocks, however, we must generally go to coast-cliffs to find good exposures. 



Usually no topographical boundaries between different formations can be 

 drawn. For instance, the mountains of Palaeozoic contact-rocks on the 50th. 

 Parallel are very low and flat. It gradually rises up to the region of crystalline 

 schists on its side, while further on we find ordinary Palaeozoic sediments, to which 

 they make topographically a gradual transition. Only on the main watershed of the 

 Northeastern Mountain-land, the above-mentioned wild sceneries begin to appear. 



The Mesozoic region on the 50th. Parallel, to the west of the Poronai river, also 

 shows high cliffs on rivers. There are certain high mountains as Aimiyama. on 

 both sides of which usuall}' quite different conditions of atmosphere are observed. 



The height of the mountains in Sakhalin are only roughly estimated in former 

 publications. Where actual surveys were made in recent times quite a different 

 result was presented in the numbers. On the east of the Median Depression, the 

 height of 900 meters near Okimiyama will be taken as one of the highest elevations. 

 On the west we have about i lOO meters on the Aimiyama, about 1200 meters 

 estimated b>' KAWASAKI for the Ninkutnupuri, which he ascended, and about lOOO 

 meters estimated for Mount Spanberg etc. 



