NO. U.j MINERALOGICAL C OMPOSITION OF THE SAMPLES. 43 



fore reasonable to suppose that a large proportion of the minerals are of 

 primary origin. 



The proportion between the various heavier minerals exhibits rather 

 great variations in the various samples. The opaque particles are made up 

 for the most part of magnetite, but some of them may also consist of the 

 previously mentioned iron concretions. This is true also of the greater num- 

 ber of the class named "Aggregates, Concretions, etc." by which is meant grains 

 that are only very slightly transparent, but which obviously do not consist 

 of a single crystal. If the latter be the case, the particle is classed with the 

 mineral in question. The iron concretions, as we have already said, are for 

 the most part formed upon the sea-bottom itself, round some one or other very 

 ferruginous mineral, most frequently magnetite ; and thus the sum of the figures 

 in the first two columns gives the approximate quantity of magnetite deposited 

 in the sample. The various remaining samples do not differ much in this 

 respect. 



But the proportion of garnets is remarkable. Particularly large quan- 

 tities are found in samples 7 and 9, which indicates that Asia's most 

 northern peninsula consists very largely of garnetiferous rocks, (especially 

 crystalline schists), some of which, in certain places, are found in situ. 

 According to Nansen the strand on Reno Isle one of the Kjellman group, 

 was red with garnets, and the micaceous clay at the same place also con- 

 tained them in abundance. As it appears impossible that samples 7 and 9 

 can have obtained their materials from such a source we must assume 

 that there are also garnet-bearing rocks at other places farther east- 

 wards. The strikingly small quantity of garnet in No. 15 can only imply 

 that this mineral must be exceedingly poorly represented in eastern Siberia 

 whence the sample in question obtained the greater part of its material. 



The percentage of hornblende in the samples is very characteristic. 

 No. 1 has quite a considerable quantity, but all the other samples along the 

 Siberian coast have an infinitesimally small amount. As hornblende is generally 

 one of the commonest minerals in quartz sand, and as it is also very charac- 

 teristic and easily recognised in the preparations, it is difficult to imagine any 

 other reason for this circumstance than that the great majority of rocks in 

 northern Siberia must be almost destitute of hornblende, but on the other hand 

 particularly rich in augite, as may be gathered from the generally considerable 



