66 GEOLOGICAL MEMOIRS. 



spar crystals, and, taking up tlie niucli more soluble lime, allowed 

 the less soluble carbonate of zinc to separate itself and be deposited, 

 together with some of the other carbonated salts, in the place of the 

 isomoi-phous carbonate of lime, the crystals thus formed having the 

 appearance of large perfectly developed zinc-spar crystals ; some, 

 however, with rough surfaces, as if a mass of small zinc-spar crystals 

 was covered with regular calc-spar crystals. 



[T. R. J.] 



On the Fossil "Wood collected during Middendorf's Travels 

 in Siberia. By Prof. Goppert. 



[Sibirisch. Reise, I. i. 10, pi. 7-10, and Leonhard u. Bronn's Jalirb. fiir 

 Mineral, u. s. w. 1850, pp. 126-128,] 



From the Tundra to the river Boganida in 71° N. lat., the fossil 

 Finites Middendorffanus, Gopp. (pi. 7. figs. 1-4) *, occurs ; the 

 wood is permeated by carbonate of lime ; the structure is similar to 

 that of the existuig Pines. From the banks of the river Taimyr in 

 74° N. lat. three species are obtained. The characters of one spe- 

 cies (pi. 7. figs. 5-17 and pi. 8. figs. 15, 16) are rendered indistin- 

 guishable by reddish brown oxide of iron ; it is very similar, both 

 in outward appearance and in the thickness of the annual rings, to 

 some fragments from certain deposits at Berhn and in Silesia ; an- 

 other, converted into shining black coal, is the P. Baerianus, Gopp. 

 (pi. 8. figs. 12-15); and the third (pi. 8. figs. 17-20), sihcified 

 and having the appearance of a greyish brown hornstone, is so much 

 weathered, that nearly all the organic tissue between the sihceous 

 casts of the cells has disappeared ; hence no specific determination 

 can be arrived at. 



On the banks of the river Taimyr, in 75° N. lat., two fragments 

 of wood were found in the immediate neighbom'hood of a skeleton of 

 a mammoth, and apparently under similar geological conditions. 

 These were but shghtly changed ; they had the appearance of having 

 been for a long time in the water, and their specific gravity was less- 

 ened. One of the specimens is identical with larch-wood (Larix 

 Europcea, L. Sibiinca, L. peadida, L. microcarpa, and the fossil 

 Finites protolarix, Gopp.), and cannot be specifically distinguished; 

 whilst the other is identical with fir-wood {Finns abies or picea, 

 Abies Sibirica, Finns picta, and others). 



None of the above fossil woods are apparently older than the ter- 

 tiary formation ; and the last two (subfossil) species, found near the 

 mammoth, are indistinguishable fi'om the existing larch and fir spe- 

 cies of Siberia. The place where they were found, however, is far to 

 the north of the districts occupied by the existuig species ; they must 

 therefore have been carried by river floods, probably in company with 

 the mammoth, from more southerly districts to the spot where they 

 were found. 



* The plates do not accompany this translation. 



