VOL. LXVI.] PHILOSOPHICAL TRANSACTIONS- ]01 



comes on very readily. The cavities formed by the iron are equally filled up 

 with a kind of fluor, which for the most part is of a clean, transparent, amber 

 colour, cuts glass, has none of the properties of scoria, and forms, according to 

 the hollows it fills, various roundish grains or drops, very glossy and clean, on 

 their surface, having one or more flat surfaces. This fluor is extremely brittle, 

 and thus, by cutting off any part of the mass, this substance is lost, and comes, 

 off partly in grains, and partly in form of a coarse powder of vitresceiit matter. 

 The whole mass has no regularity of form, but resembles a large, oblong, 

 somewhat flattish pebble, and is coated on the outside with a matter resembling 

 some blackish brown iron ores. This coat however covers not the whole mass ; 

 it is also very rich of iron, and even the transparent fluor yields some pounds of 

 iron in the hundred. Whoever will consider the mass itself, or large specimens 

 of it, will not have the least doubt of its being worked by nature, since it has 

 no one character of scoriaceous matters melted by artificial fire, or commonly 

 found among volcanoes. ' 



With regard to these, as seeming a probable place where this mass could have 

 been formed, it may not be amiss to add the following observations. The 

 mountains, where it was found, are part of the northern extensions of that 

 mighty chain of mountains which runs from west to east through Asia, and 

 forms the natural limits of Siberia, with the Desarts of Tartary, the Mongols, 

 and the Chinese Empire. From the river Irtish, where the forehills and lower 

 parts of these mountains yield, in a great many places, the richest silver ores 

 the chain runs generally somewhat to the north-east, and therefore extends to 

 the east of the river Jenisei, over a much greater part of Siberia than what it did 

 before. Its forehills are almost every where composed of rocks and strata 

 rising very steep to the horizon, and the horizontal layers are only found in the 

 level country, in which also all kinds of fossil and petrified sea productions are 

 very scarce, and only found in the very northern parts of Siberia. Common 

 flint is as scarce in Siberia as petrifactions, and nothing like productions of vol- 

 canoes any where to be found. Even in some places, where hot springs are 

 found, these seem only due to collections of pyritae of no great extent, and the 

 slight earthquakes which are sometimes observed about the river Irtish, and 

 more frequently about the lake Baikal, certainly rise in tlie very neighbourhood 

 of this lake and of the Noor Saissan, which gives rise to the river Irtish ; and 

 about these lakes never any thing like a volcano has been heard of, nor is there 

 one known in the northern part of Asia, except those in Kamtschatka and the 

 islands newly-discovered between that peninsula and the continent of North 

 America. The same may be assured of the Urallian mountains, a ridge 

 that runs from south to east, and continues to the very Northern Ocean and 

 Nova Semlja, being o'lly interrupted by the Strait of Waygat. It is this 



