18 
MUSEUM BULLETIN NO. 23. 
The line AB drawn perpendicular to the isobases shows the 
direction of tilt or maximum uplift. In the southern part of 
the district the direction of tilt is about north 26 degrees east. 
Near Beaverton the direction changes to about north 22 degrees 
east. In the northern part, the direction is apparently irregular, 
but in general shows a marked change to a more northerly course. 
In the Balsam-Cameron Lake area, the direction is nearly due 
north. 
A small fold and fault, the location of which Is shown on the 
map, occurs and is seen in cross-section in a cutting in Trenton 
limestone along the Trent canal near Kirkfield (Plate III). 
The fault appears to be recent in age. It is reverse in character 
and is evidently due to a slight buckling or thrust. It was 
found by cleaning out the fault surface that the walls were slick- 
ensided in places in a nearly horizontal direction indicating a 
transverse movement. The fact that the fault occurs just where 
the marked change in the trend of the isobases occurs and the 
character of the fault suggests that there was a casual relation 
between the uplift which caused the irregular deformation of 
the Algonquin beach in this area and the development of the 
fault. The isobases are shown by broken lines in the Kirkfield- 
Balsam Lake area, for it is not known exactly how they should 
be drawn. It is possible that there are slight offsets in the iso- 
bases in the faulted area. 
The marked change in the rate and direction of tilt or maxi- 
mum uplift in the northern portion of the district seems to show 
that there is a sort of "hinge line” or zone here. The region 
north of this zone was affected by a set of movements which did 
not affect or only slightly affected the region south of this zone. 
The direction of maximum uplift which was the result of the 
later movements was more nearly north than that of the earlier 
movements. 
The profile of the warped Algonquin water-plane along the 
line of tilt AB is intended to show approximately the character 
of the differential uplift which deformed the water-plane. 
In the construction of this profile accurate topographical 
maps drawn on a field scale of 4,000 feet to the inch were used, 
from which the location of the different points at which the alti- 
