716 STEINAR FOSLIE 
tation proceeded quite 7 sziw and is confined to the crystal- 
lization period. Further we have learned that the squeezing 
differentiation gives results which in many respects are similar to 
those of gravitative separation. In the one case the liquid is 
removed from the crystals, in the other case the crystals from 
the liquid. 
There is only one point left which cannot yet be explained in 
detail: how some of the primary olivine crystals could be brought 
to accumulate or conglutinate at certain places. On this point, 
therefore, we can only state the fact and remark that any suppo- 
sition of immiscibility of olivine with the rest of the magma, 
resulting in the formation of fluid drops of olivine, would not help 
us, but be in opposition to several of the above-stated facts. 
As will easily be seen, the special differentiation type of Raana 
is not apt to occur very frequently. It presupposes the following 
conditions: (1) the crystallization must take place under lateral 
pressure; (2) it must take place completely in situ, in a closed 
room without supply of new magma during the process; (3) gravi- 
tative separation must not play a prominent part. 
In the same district we meet a somewhat different type of 
squeezing differentiation, one which will prove to have a more 
general occurrence in orogenic folding zones. It occurs when the 
central part of the eruptive mass is not—as in Raana—protected 
against lateral pressure. A short statement of it is here added. 
THE AMPHIBOLITE SERIES 
As mentioned in the first part of this paper, in the folded 
mountain region there occur considerable quantities of femic 
eruptive rocks very intimately injected into the schists and com- 
pletely recrystallized through dynamic metamorphism. They 
do not occur in so extensive individual masses as do the fresher . 
rocks of the Raana type, but they are much more widely distributed. 
Chemically they have diabasic composition and differ from the 
corresponding rocks of the Raana field in carrying more iron in 
proportion to magnesia, more sodium, titanium, and phosphorus. 
On account of the total parallelism of all eruptive injections in 
the district, direct observations of relative ages can generally not 
