378 MWS OVS AAIE STAC IES, 
lumpy aggregation of the feldspathic constituents. During the sum- 
mer of 1894 the author visited the region from which this rock was 
obtained and studied its relations in the field, subsequently studying 
in the laboratory the material obtained. 
The rock was found to occur at High Rock, an apatite mine on 
the west bank of the Du Lievre River about twenty miles above Buck- 
ingham, in a series of dikes intersecting quartzites, and pyroxenites. 
In general the rock has the composition of a syenite though in places 
carrying more or less quartz, and is often associated with the apatite 
deposits, but no attempt is here made to show their genetic relation- 
ship. 
The dike rock in its various phases shows more or less evidence of 
dynainic action, and the term syenite-gneiss is applied to it. It pre- 
sents three distinct phases which the author designates as coarse-grained 
syenite-gnetss, ellipsoidal syentte-ynetss and streaked syenite-gneiss. The 
first consists of a coarse-grained mixture of microcline and monoclinic 
pyroxene with a small but variable amount of quartz. The rock is 
divided into irregular blocks by obscure seams which apparently rep- 
resent recemented cracks. In the second phase it consists of irregu- 
larly ellipsoidal or ovoid masses of feldspar and some quartz separated 
by narrow anastomosing partitions of green interstitial material, chiefly 
augite. Frequently the crystals of pyroxene, which are elongated in 
the direction of the prism, lie transverse to the interstitial layer and 
thus present a more or less pronounced radiate appearance. From 
the rounded ellipsoidal forms the feldspathic lumps vary to more and 
more flattened forms until the structure merges into the third phase, in 
which the pyroxene layers are arranged in parallel bands alternating 
with somewhat thicker feldspathic layers. Here there is marked dimi- 
nution in the size of the grains, while quartz becomes relatively more 
abundant. Large crystals of apatite appear in places inclosed in the 
ellipsoidal rock, and having the ellipsoids arranged concentrically 
about them. Masses of apatite also occur in the streaked rock, 
crushed to a more or less granular, saccharoidal condition, and around 
them the streaks of pyroxene curve concentrically. 
Under the microscope the coarse-grained rock is found to be 
composed chiefly of microcline, with a much smaller proportion of 
augite and a variable but usually small amount of quartz. The rock 
is intersected in various directions by fine, granular bands, made up of 
microcline and plagioclase, the latter usually containing small nodular 
