600 THE FRESH-WATER LOCHS OF SCOTLAND 
lake-basin at one-third of its entire length from the south-west end 
is divided into two parts by a submerged ridge, covered by not more 
than 942 feet of water. Near the shore are considerable areas where 
the water has a depth of only 1 20 feet ; the largest of these areas 
occur off the mouth of the Selenga, which brings down so much 
sediment as to form an immense alluvial cone, the Chivirkulskaya 
Bay, the delta of the LTpper Angara and the Little Sea ; yet only 
8 per cent, of the lake-floor is covered by less than 30 fathoms 
(180 feet) of water. Except off the deltas and the small Ushkanii 
Islands (near Svyatoi Nos Peninsula) the 100-fathoms line runs very 
near to the shore, especially along the north-western coast. Svyatoi 
Nos (Holy Cape) is a large peninsula protruding from the eastern 
shore of the lake opposite to the island of Olkhon, about midway 
between the northern and southern ends. The extreme northern end 
of the peninsula presents a high, wooded, almost vertical ridge with a 
craggy summit, from which flows a liquid called "Imusha"" by the 
Tungus, natives of the district. According to Georgi,^ it is a kind of 
mineral oil (vitroleum unctuosum) : others believe it to be produced 
by the decomposition of the excreta of cormorants, herons, sea-gulls, 
and other birds, which come to the island in infinite numbers, mainly 
during their migration. Springs containing an oily liquid very much 
like naphtha have been discovered at the bottom of the Baikal opposite 
to the mouth of the River Turka. Floating wax, or " bikerit,'" used 
by the inhabitants as a medicine for rheumatism and scurvy, is got on 
the surface at this part. It burns very quickly with a bright flame, 
and leaves much soot. This substance was subjected by Shamarin 
in Irkutsk to analysis by dry distillation, and volatilised at 140° C. ; 
it contained 8'44 per cent, of liquid distillate (burning oil) and 61*17 
per cent, of solids (paraflin of the best quality). 
The numerous rocky fragments torn from the mainland found all 
round the lake, the islands lying in close proximity to the shore and 
retaining traces of their former identity with the surrounding 
mountains, and the great depth of water near the clifl's rising above 
its surface, all testify to the violent origin of the lake. Georgi ^ 
believes that the area occupied by it is the continuation of the valley 
of the Angara, and that the basin of the lake was formed by a 
sinking produced by a violent earthquake. 
Kropotkin ^ considers Lake Baikal a " twin lake,'' the north end 
of the southern basin being continued by the valley of the River 
Barguzin, and the south end of the northern basin lying behind the 
1 Guide to Great Siberian Eailwa,y, p. 330, St Petersburg, 1900. 
2 Ibid., p. 331. 
2 Cited by Suess, Das Antlitz der Erde (English translation, vol. iii. p. 53, 
Oxford, 1908). 
