34 ARCTIC BASALT PLATEAU 
The two rocks analysed from these localities, whose geological 
history no doubt in time and in cause of volcanicity will be common, 
differ conspicuously in their mineralogical and chemical composition, 
the one being a typical alkaline rock, the other apart from the vesicle 
minerals showing a distinct character of the calc-alkali-series and 
approaching to a common basalt; only the high alumina content 
makes such a calc-alkalic affinity at least doubtful. To facilitate 
an immediate comparison the two analyses are tabulated together 
as follows: 
l | 2 | 
| SiO, 44.43 | Alas .| 
| ALO, 18.61 11.69 | 
‘FeO, | 3.48 541 | 
| FeO 6.62 7.94 
MgO 101 | 1088 
| CaO | 6.78 | 9.58 
_Na,O Pee 8 
| KO | 0.92 3.08 
| H,O at 110° | 1.58 | 0.11 
HO SS 110%) 1020 a a 
LIGOR | 0.2 | none | 
| TiO, eee oh irene | 
11805 | 0.33 | 1.25 
| MnO ot Ops tle tes One 
| BaO | 0.02 | 0.0 | 
996 | 99:65 
Spec. gr. 2.861 3.045 | 
This contrast is a typical one for the basalts of the Arctic region, 
as stated by v. Wolff! and others, yet in no part, as known to the . 
writer, pronounced in such an extreme manner as in the case in 
question; the mixed character of the Arctic province was explained 
by its situation between the Atlantic and Pacific provinces too, 
being on both sides limited by them. In no part doubting the 
peculiar character of this province the writer wishes to direct the 
1F. v. Wolff, Der Vulkanismus. I, pag. 152 (1914). 
