296 
endeavoured to apply this hypothesis to large granitic intrusions 
of irregular habit. Nevertheless the applicability of the hypo- 
thesis does not seem to be sufficiently proved in any such case, 
and in the present instance it is easy to see that we are not 
concerned with phenomena comparable to those which are ex- 
emplified in the laccolites. This is shown by the following 
facts: — (a) The strata of the country rock are cut off almost 
vertically by the batholite from sea level to an altitude of more 
than 1100 meters. If the intrusion was of the laccolitic kind 
the contact surfaces must as a rule be parallel to, and not 
perpendicular to, the bedding planes of the country rock. 
(b) The cover of the Ilimausak batholite is concave or trough- 
like, and occupies a sunken position in relation to the adjacent 
parts of the earth crust (see Fig. 26 and Fig. 27). The cover 
of a laccolite is convex or domed and is elevated in relation to 
the surroundings. It is to be concluded, therefore, that the 
intrusion of the Ilimausak batholite is due to processes diffe- 
rent from those which produce laccolites. 
(IV.) According to the assimilation hypothesis the magma 
is supposed to melt its way upward, and thus incorporate a 
large portion of the country rock?. 
This hypothesis is in accordance with the general form of 
the Ilımausak batholite, but it does not seem to be satisfactory 
from a chemical point of view. This is indicated by the fact 
that most of the abyssal rocks of Ilimausak are characterized 
by certain chemical peculiarities of composition — extremely 
large quantities of sodium and zirconium — which seem to pre- 
clude the assumption that the bulk of the batholite has originated 
from the assimilation by any magma of large portions of the 
country rock. Further the comparison of the Julianehaab district 
with that of Christiania furnishes an argument against the sup- 
1 A. MicHEL Lévy, Contributions à l'étude du granite de Flamanville. 
Bull. des services de la carte géol. de la France У, No. 36, р. 35 (1893). 
A. Lacroix, Le granite des Pyrénées. Ibid. X, No. 64, р. 62 (1898). 
