HURONIAN FORMATIONS, TIMISEAMING REGION. 
13 
dykes appear to be a widespread feature and suggest an equally 
widespread exposure of the formation which they intrude, to 
erosive agencies. Nevertheless, the limestone and greywacke 
are conformable with the adjacent formations and maintain a 
uniform thickness along their exposed edges for the entire 5 
miles explored. There does not yet appear, therefore, to be 
convincing evidence of any important unconformity within 
these formations. 
The upper limestone grades through 15 feet of greywacke 
and impure quartzite into a white, feldspathic quartzite 1,100 
feet thick. At most places this is terminated by the uncon- 
formity between the lower and upper series, but at one point it 
grades up into 40 feet of interbedded quartzite and siliceous 
greywacke of dark grey colour before being interrupted by the 
unconformity. 
The conglomerate < and quartzite members of the upper 
series found beneath the slate conglomerate in Bruce and Blind 
River areas are lacking in this area: a boulder conglomerate 
exceeding 400 feet in thickness rests directly upon the greywacke 
and quartzite of the lower series. The lowermost 100-150 feet 
of this conglomerate, however, is really a well stratified formation 
consisting of thick-set beds of rounded pebbles alternating with 
beds of coarse quartzite. Above this it merges into a typical 
boulder conglomerate — pebbles and boulders, up to 6 feet in 
diameter, of a great variety of rock materials being scattered 
thickly and promiscuously through a dark grey grit or grey- 
wacke matrix rich in dark minerals. The evidences of uncon- 
formity between this conglomerate and the lower series are 
positive: the dip of the conglomerate beds differs as much as 
15 degrees from that of the underlying quartzite; the conglomerate 
contains large fragments and rounded boulders of the underlying 
quartzite and greywacke ; and the boundaries of the conglomerate 
lack the parallelism with the boundaries of the formations of 
the lower series that these lower formations show toward one 
another. 
Espanola Area. 
This area does not contribute anything to the Pre-Cambrian 
successions that is not already found in one or other of the areas 
