
B. N. A. BOUNDARY COMMISSION. 


on freshly fractured surfaces. It has a strike of N. 76° E., with ad 
an angle of 55° northward. The part on the mainland, north of th: 




particles are barely visible, and which includes small crystals of py 
1 It is somewhat disturbed, but may be stated to have an average 7 
eae) N. 35° W. < 80°. This quartzite belt occupies a width of about or 
third of a mile, and unless unknown complications affect the strata, p 
| have a thickness of at least 1,500 feet. sl | 
ae i 70. Five and a half miles west of this point, and in immediate juxta. 
= position to the northern edge of the granite mass, a quartzite, so ae 
| altered that it might almost be called a sandstone, unexpectedly appears. 4 .- 
It is fine grained, and grey in colour, and is penetrated by a dyke of ‘e 
is granulite with quartz seams, and small included crystals of molybdenite. ve 
It has a dip of 8. 37° E. < 63°, or toward the granite, but this is 
‘no doubt local, and due to folding connected with the extrusion of that Ke ‘a 
mass. It probably represents the same band of quartzite as that last = 
described, and if so, the northern edge of the granite runs obliquely to 
the strata to such an extent as to cover or remove the whole of the 7 P 
o Ve 
, 































ees western extension of the underlying conglomerate series. . 
71. In describing the details of rocks of the remaining portion of the 
; lake, the order of those beds seen along the shore of the mainland be- 
iy tween the North-west Angle, and Rat Portage, will be followed. That * 
a part of the coast-line is laid down with sufficient accuracy on the map to 
i enable points to be fixed with some degree of certainty. In discussing 
each well marked series of beds, it will then be traced eastward as far as _ ay 
my observations extended. The accompanying general section (Sect.3) 
will be found of use in following the descriptions, but must be accepted — 
as only accurate in a general way, as subordinate intercalations of — 
“A 
slates and shales, occurring among preponderating greenstone and con- 
ay 
glomerate beds, have not been indicated. Indeed, where the rocks have _ 
suffered great metamorphism, as in the neighbourhood of the various 

granitic masses, it is exceedingly difficult to lay down precise boundaries; 
and such accuracy could only be the result of long and patient tracing 
out of well marked beds as datum lines. bet 
72. The rock immediately succeeding the last described quartzite in 
the Smal] Promontory, is a dark-green crystalline hornblendic material, 
with laminw of chlorite. It might be an eruptive rock, but rather seems 
to belong to the series of greyish and blackish schists next in order, 
which, unless overlooked among the much altered rocks a few miles 

