SS Pentti Eskola « c sS5 45 Una 
data agrees fairly well with the skarn theory. It is only 
by combination of these two assumptions that we can wholly 
understand the genesis of the rock under discussion, and 
this rock becomes therefore of general petrogenetic interest. 
We have here a concrete case, illustrating Daly's principle 
of the origin of alkaline rocks by mutual action of magma 
and 'limestone I). The granitic magma has lost its excessive 
silica and the greater part of its iron oxides, both transferred 
into the limestone to form andradite-skarn. The mechanics 
of this process are still somewhat ill understood. Gold- 
schmidt's theory of ferric fluoride or ferric chloride as the 
primary emanåtion from the magma cannot be proved when 
no halogen compounds are to be found. In every case, 
the transfer of substance is a matter of fact. In the resulting 
skarn we find trivalent iron, whilst in igneous rocks that have 
not assimilated pneumatolytic contact-products the ferrous 
iron dominates. We do not know which stage is the original - 
one; if the:magma is charged with ferric halogenides, a redue- 
tion to the ferrous stage would be the Tegan event at the 
consolidation of rock-magmas. 
Whatever may be the method of the metasomatosis, its 
result was to change the original granitic magma to syenite- 
aplitic. If nothing was added to this magma by: further 
assimilation, it should have developed chiefly feldspars when 
consolidated. Such syenite-aplites, in part with a little 
andradite, are in fact found forming a large part of the south- 
eastern half of the sviatonossite mass, passing by gradual 
transition into aplitic granites on the one side and to ordinary 
sviatonossite on the other side. This is only what is to 
be expected on the hypothesis that skarn was first formed 
in 'the shattered blocks of limestone and later assimilated 
when sunk to deeper levels. 
There the assimilated andradite-substance crystallized 
once more as andradite, being one of the earliest constituents 
to separate. 
As the skarn-andradite contains as ul as 9 percent 
/å 2) RB. A. Daly, Bull. Geol. Soc. America, Vol. 21, pp. 87—118 (1910), and 
»Igneous Rocks and their Origin, pp. 410—445 (New-York 1914). - 
