186 Scientific Intelligence — Geology and Mineralogy. 



Gray inferred that they belonged to some coniferous tree or shrub, 

 and probably to a kind of spruce fir, rather than to a true pine. 

 This inference was borne out by the examination of thin slices of the 

 wood by the microscope. The woody fibre tvas very beautifully and 

 distinctly marked with the circular discs that are characteristic of all 

 coniferous wood. The structure agreed quite perfectly with that in 

 similar branchlets of the common hemlock spruce.-^ — American Jour- 

 nal of Science, Literature, and Arts, Now Series, vol. iii,. No. 9, 

 p. 436. 



3. Large Plates of Mica. — The Vittim is remarkable for a 

 mica mine, which is said to produce the largest and Clearest sheets of 

 the substance in the world, some of them being quite pure to the ex- 

 tent of two feet and a half ^qi\2i,vG.— Narrative of a Journey round 

 the World, by Sir George Simpson, vol. ii., p. 334. 



4. Lake Baikal. — Lake Baikal is about seven or eight hundred 

 versts in length, and about seventy or eighty broad at its widest 

 part. The waters are as clear as crystal, everywhere deep, and in 

 many placies unfathomable. Besides the humberless cascades that 

 rush down its walls of mountains, it receives many rivers, more es- 

 pecially the Angara at its northern extremity, and the Selonga on 

 its eastern side, towards the south ; and its single outlet, in spite of 

 the superior claims of the Selenga, on the double ground of position 

 %nd magnitude, professes in its name to be a continuation of the re- 

 mote and comparatively inconsiderable Angara. The two Angaras 

 are sometimes distinguished from each other as Upper and Lower. 

 The quantity of water which issues from the lake is believed to be 

 vastly less than that which flows into it, the difference being, in all 

 probability, too great to be explained by evaporation alone. In this 

 view uf the thing, a large portion, as a matter of course, must be ab- 

 sorbed, an operation which the volcanic origin of the huge hollow 

 may be supposed likely to facilitate. In fact, the lake presents cer- 

 tain features which have induced individuals to infer that it has a 

 subterranean communication with the ocean. It is the only body of 

 fresh water in the world that possesses phocoe or seals ; and when 

 agitated, in the way already mentioned, by invisible curves, it throws 

 up to its surface quantities of small fish, which are never seen at any 

 other time. In illustration of the mysterious agencies of nature, 

 which produces the same ends by contrary means, I subjoin two pas- 

 sages from Baron Wrangell's interesting work. 



" These flat valleys are occasionally filled with water, by the over- 

 flowing of the rivers in spring, when they form lakes of various 

 sizes, all very full of fish. The intense frosts of winter cause large 

 clefts in the ground, by which the water drains off", sometimes in the 

 course of a single year, sometimes in several. 



"A curious phenomenon occurs in the lakes in the vicinity of the 

 village of Alasey a. In the middle of winter, the water sometimes 

 suddenly disappears without any side channels being visible. In 



