GEOLOGY 195 
These dark gneisses are inclosed and penetrated by the granite- 
gneisses, and probably represent portions of the ancient bedded 
series. 
Beyond Cape Wolstenholme, gneisses occupy the eastern coast 
of Hudson bay to within a short distance of Cape Smith, where 
a high ridge of trap runs inland in a northeast direction and 
has a width of several miles. Further south the gneisses again 
predominate along the coast to the Portland promontory in 
latitude 58 n. 
GEOLOGY OF THE NORTHWEST SHORES OF HUDSON BAY. 
The following account of the geology of the northwest shores 
of Hudson bay has been compiled from observations made dur- 
ing the trip of the launch from Winchester inlet to Chesterfield 
inlet in September, 1903. These are supplemented by the notes 
made in May, 1904, while making a track survey from Cape 
Fullerton to the entrance of Chesterfield inlet. The observations 
to the north of Fullerton were made by Mr. Caldwell, in April 
and May, 1904, while on his surveying trip to the head of 
Wager inlet; to these are added observations by the writer made 
on a boat trip along the coast later in that spring, on the way 
to and from Southampton island, when the rocks of the main- 
land were examined as far north as Yellow bluff. 
The rocks seen along the shore between Chesterfield and Win- 
chester inlets are largely a flesh-red to pink mica-hornblende 
granite-gneiss, often only slightly foliated, and varying in tex- 
ture from medium to coarse-grained. These are associated with 
broken bands of dark-gray or red gneisses, usually very quartz- 
ose, and containing a considerable quantity of mica and horn- 
blende, the latter often partly decomposed to chlorite. These 
gneisses have evidently been cut and broken by the intrusion of 
the granite-gneisses. Many veins of pegmatite cut all these 
rocks; it consists chiefly of red or violet feldspar with much 
quartz, and in some places large crystals of black hornblende. 
