Dikes . 
227 
groupings of sericite about plates of ilmenite or iron oxide are 
noticeable. The mica radiates from the iron inclusions out some 
distance into the mass of the rock, regardless of pressure lines. 
In such cases, the iron is oxidized and the arrangement suggests 
chemical action as the cause, the changes originating with the 
inclusion itself. 
In most of these schists found in Beaver Tail there is an 
abundance of rutile occurring in sagenite webs, in needles, 
and in genal twins. This mineral is very abundant in the met¬ 
amorphosed rocks, both those of clastic and igneous origin. It 
is doubtless a metamorphic mineral in all cases. The perfection 
of the crystals found in the clastic rocks certainly precludes 
the supposition that they could have been washed out of the 
granite rocks and redeposited in their present position. 
The schists of the western portion of Beaver Tail are coarser 
than those already described. They are also more folded and 
faulted. The folds are closely compressed and they are so devel¬ 
oped in some cases as to result in over thrusts and overturned 
folds. The strata on a small but elaborate scale are faulted, 
contorted and crumpled, all indicating violent and sharp dynamic 
action, though the folds resulting are rarely over ten feet across 
the base. The contortions of the rocks, however, are of a very 
extreme character. The pebbles and grains of quartz are flat¬ 
tened and stretched out to an extreme degree. Fracturing rarely 
occurs, but by the slow pressure which must have existed under 
the circumstances the pebbles are flattened to great degree. 
We have passed in review the deposition and deformation of the 
schists, a great series which, in spite of the degradation which 
has taken place, now amounts to a thickness of 1,200 feet on this 
island alone. 
DIKES. 
While the process of metamorphism was in progress or before 
its existence there occurred an eruption of igneous material in 
the form of narrow dikes. These dikes are found in the granite 
area and in the schists. They are folded and faulted and have 
even received a schistose structure in common with the country 
rock about them. The dikes are five in number, all have a general 
