338 
as is well known, is usually taken as an indication that the 
rocks have been produced from a parent magma by some kind 
of progressive differentiation, but it would by far exceed the 
scope of the present report to give any discussion of the pro- 
blems which this view involves. Here we need only mention that if 
the rocks of the unstratified batholite have been produced by differ- 
entiation, that differentiation must have been prior to the intrusion. 
The stratified batholite of Ilimausak. — The chemical 
compositions of the rocks of the stratified batholite show much 
more complicated relations. If the results of all the analyses 
are represented in a variation diagram of the ordinary kind!, it 
will be found that the variations are pictured as highly irregular 
curves. It is not even possible to arrange all the analyses into 
one series, because several rocks with almost identical silica 
percentages differ widely in their other constituents (compare 
analyses 5 with 14, 6 with 15). A glance at the accompanying 
figure (Fig. 32) in which a number of the nepheline-syenites are 
graphically represented will show the same fact (comp. N, with K,). 
It is scarcely possible in the present state of knowledge 
to arrive at a quite satisfactory interpretation of the genetic 
relations between the large number of chemically differing 
rock types which occur within the stratified batholite, although 
in some details a probable interpretation may be given. Some 
of the variations appear to be attributable to a differentiation by 
fractional crystallization combined with the effects of gravity in 
situ, while in other cases the variations are probably due to 
successive arrivals of different magmas. 
From a chemical point of view the rocks of the stratified 
batholite may be comprised under three main divisions: (1) the 
granite; (2) the rocks of the transition zone; and (3) the ag- 
paites, the latter name” being chosen as a convenient term for 
1 A. Harker, Natural History of Igneous Rocks, 1909, p. 118. 
? Agpaite from Greenlandic agpa, auk, pl. agpat, the name of a locality 
on the S. side of Tunugdliarfik, within the area of the batholite. 
