. 
244 R. D. Irving—Divisibility of the Archean. 
tions would remain uncovered. Indeed, as any one glancing 
at the accompanying map must admit, the line of contact here 
is singularly free from such irregularities as might on this vieW 
reasonably be expected to occur. 
Summarizing, then, I find proof. of the existence of a great 
unconformity between the two formations we have been fol- 
lowing :— 
1. In the manner in which the regularly succeeding belts of 
the higher series traverse the courses of those of the lower. 
2. In the strong contrast between the two series as to roc 
kinds, the bedded members of the lower series havin arrived 
at a nearly complete recrystallization, while those of the higher 
are but little altered. 
3. In the highly folded and contorted condition of the lower 
series, as contrasted with the unfolded condition and simple 
stratigraphy of the higher. 
: th the striking contrast between the contacts of the gran- 
ite with the lower schists and with the higher slates, the for- 
mer being invaded by it in an intricate manner, the latter never, 
when the two come together ;* 
* Granite in veins and intersecting masses occurs among the upper mica schists 
of the Penokee series (see map) but this always of a different character from the 
granite at the southern contact which has, as yet, never been found to inte 
the slates 
