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portions of the hybrid magma have gradually moved upward 
into the upper portion of the batholite, and are thus separated 
both from the syenite and from the sandstone. The final result 
of the movement should be an upper layer of granitic magma 
resting on the syenitic, and taking into consideration that the 
greater part of the syenite, as previously mentioned, must be 
supposed subsequently to be replaced by the agpaitic magma, 
this is in harmony with the actual mode of occurrence of the 
arfvedsonite-granite at Ilimausak. 
It will, thus, be seen that the assimilation hypothesis is 
not in this particular case disproved by actual observation. On 
the other hand, no definite proof has been found, and the 
question of the origin of the [limausak granite is therefore left 
undecided. The above considerations are mainly intended to 
show that the assumption of assimilation, operating on rather 
a large scale within moderate depths of the earth’s crust, may 
be in some cases a reasonable working hypothesis. 
