ANIMIKIE ROCKS ON THUNDER BAY. 373 
quite large areas, filling corners between the feldspars. This rock is as near 
to the augite-syenites as to the orthoclase-gabbros! The smaller dikes, 
usually under twenty feet in width, are of a denser rock, the only section of 
which examined showed a very highly augitie diabase allied to the ashbed 
kinds. All of these dikes have a general northeasterly trend, but the 
amount of easting lessens as they are followed northeastward. This may 
be seen in a single dike in the case of the Victoria Island group of islands, 
which to the southwest trends N. 60° E. and to the northeast N. 52° E. 
Of the crystalline rocks interbedded with the slates, the greatest masses, 
often over a hundred feet in thickness, appear to be olivine-gabbros and 
orthoclase-gabbros, identical with the two kinds of rocks of the broader 
dikes. These masses beyond question are interbedded with the slates, and 
though no direct connection was seen between them and the dikes, from 
the nature of the rocks such a connection is probable enough. The rock 
of the great mass capping the bluff just north of Sucker Brook, for instance, 
is an orthoclase-bearing gabbro very close to the dike rock of the mouth of 
Pigeon River, and on the same bluff, at a lower level, precisely the same 
orthoclase-bearing rock is seen cutting the slate, the probability being very 
strong that the two are connected. In thin section this rock shows labra- 
dorite, some orthoclase, abundant augite or diallage, partly much altered 
and partly in quite fresh, long, twinned blades, and very abundant magnetite 
in long, rod-like forms. 
Fic. 33.—Bed of intrusive diabase in Animikie slates, Pigeon Bay, Canada. 
Besides these greater imbedded masses, thinner, strongly cross-colum- 
nar beds of a dark crystalline rock are often seen. These are at times 
only four to six feet thick. They generally run in strict parallelism to the 
included slates, but in one or two places were noticed distinctly traversing 
1 To Gudee on other iende specimens brought away, the. one ae which this slice was made 
does not represent the dike of Victoria, Thompson, and Spar islands for any great distance. The other 
specimens, not sectioned, look more like some of the olivine-bearing kinds. 
