123 
the optical properties of catapleiite. These pseudomorphs are 
allotriomorphic against the felspar. 
Fluorite is not uncommon in some specimens but very 
scarce in others. It belongs apparently to the primary con- 
stituents of the rock, for it is commonly inclosed within the 
dark minerals. Thus, the arfvedsonite and the egirine-augite 
are frequently so filled with small rounded fluorite crystals that 
they get a sponge-like appearance. — A little analcime is also 
present filling small interstices between the felspar crystals. 
Chemical analysis. — An analysis of this type was made 
by Dr. С. Wintaer with the results given in the following table. 
The specimen selected for analysis was taken at North Siorar- 
suit in the transition-zone from granite to foyaite, about three 
meters above the upper boundary of the foyaite (see p. 79). As 
shown by the analysis the rock must belong to that group of 
alkali-syenites which comprises the rocks commonly termed 
nordmarkites, pulaskites, and umptekites according to the char- 
acter of their dark minerals. For the sake of comparison 
Wasurneton’s analysis of the original pulaskite of J. Е. Wırzıaus 
is given in A. The Greenlandic rock differs from the typical 
pulaskite in so far as arfvedsonite or egirine-augite in many 
Specimens of the rock is more abundant than the biotite, but 
it agrees with typical pulaskite in all essentials and also as to 
outer habit. 
It many other kinds of rocks, as is well known, the nature 
of the femic constituents is of systematic significance, but with 
rocks of the alkali series the distinction between mica-, am- 
phibole-, and pyroxene-bearing types is of very little value 
from a systematical point of view, and the above described 
rock furnishes a striking example of this fact. The pulaskite 
of the Ilimausak complex is of a well defined type, nevertheless 
it contains mica, amphibole, and pyroxene in irregularly varying 
relative amounts so that very often two slices of the same rock- 
specimen should be classed into different groups if the nature 
