HURONIAN FORMATIONS, TIMISKAMING REGION. 
25 
concession II, Aberdeen township, in Bruce area, which has 
already been described. 
Single outcrops showing this unconformity do not yield an 
adequate impression of its real importance. Little or no dis- 
cordance between the two series is recognizable, almost all the 
pebbles representing the lower series in the basal conglomerate 
of the upper series are from the formation immediately sub- 
jacent, and these pebbles are often imperfectly worn. A com- 
parison of the unconformity as it appears in various parts of 
each area and in the different areas, however, alters this impres- 
sion. The plane of unconformity, diagrammatically indicated in 
Figure 3, cuts the Bruce limestone and Mississagi quartzite of the 
lower Huronian series in Bruce area, the Mississagi quartzite, Bruce 
limestone, and greynvacke formations in Blind River area, and 
only the upper portion of the Serpent quartzite formation of the 
same series in Whiskey Lake area. Erosion, therefore, proceeded 
about 150 feet deeper in Blind River area than in Bruce area and 
about 1700 feet deeper than in Whiskey Lake area. Where the 
differences are so great the total erosion must have been con- 
siderably more. 
Nevertheless, the period of erosion was not marked by any 
notable earth movements; for the lower series is folded little 
or no more than the upper series. Also the absence or scarcity 
in the basal conglomerate of the upper Huronian series, of 
pebbles representing the higher formations of the lower Huronian 
series, taken in conjunction with the abundance of pebbles of 
granite and other hard pre-Huronian rocks, seems to indicate 
that the lower Huronian rocks were not well enough consolidated 
and cemented to resist erosion. 
These criteria place within approximate limits the duration 
of the erosion interval between the lower and upper Huronian 
series. It is certainly greatly inferior to that of the interval 
between the Huronian and the pre-Huronian. 
CORRELATION OF DISTRICTS. 
It has been shown that in Wanapitei area the upper of the 
two Huronian series consists of 4,000 feet of boulder conglomerate, 
