740 (Gai IK SLJEN IEG 
recrystallized volcanic materials. ‘Their original forms included both 
tuffs and lavas. The gneissoid granites and syenites are plutonic 
intrusive rocks within the greenstone-schists. The basic dikes are 
mainly diabase. The peridotite is older than the Cambrian sandstone 
and younger than the greenstone-schists of the Basement Complex. 
The ferruginous veins are believed to be water-deposited, and were 
formed previous to the deposition of the Lower Marquette series. 
The Southern Complex differs from the Northern Complex in 
the smaller quantity of greenstone-schists in the former and in the 
presence in it of the micaceous and hornblendic schists, and the Palmer 
gneiss. It is treated under the divisions micaceous schists, amphibole- 
schists, gneissoid granites, Palmer gneiss, and intrusives. ‘The mica- 
ceous schists include muscovite-schists, biotite-schists, feldspathic 
biotite-schists, and hornblendic biotite-schists. ‘They are thought to 
be mashed acid eruptives. The amphibole-schists include greenstone- 
schists, hornblende-schists, and micaceous hornblende-schists. ‘They 
are shown to be mashed basic eruptives. The granites and dike mate- 
rials are similar in their essential features to the corresponding rocks 
of the Northern Complex. The granites are younger than the schists, 
since dikes from them intrude the schists. The Palmer gneisses occur 
only on the borders of the granite areas, between these and the Mar- 
quette sedimentaries, and are apparently in most cases extremely 
mashed phases of the granites. 
The isolated areas of the Fundamental Complex within the Algon- 
kian are chiefly gneissoid granites and schistose greenstones, that differ 
in no essential respect from the corresponding rocks of the Northern 
Complex and Southern Complex. 
The Lower Marquette series is composed of the following forma- 
tions, given from the base upward: The Mesnard quartzite, the Kona 
dolomite, the Wewe slate, the Ajibik quartzite, the Siamo slate, and 
the Negaunee iron formation. ‘There is no break between these forma- 
tions; the series is a continuous one. 
The Mesnard quartzite is chiefly a metamorphosed sandstone. 
However, at the bottom of this formation is a conglomerate, which in 
grading into the sandstone passes through slate and graywacke. The 
conglomerate is basal, being composed of detritus from the Basement 
Complex. At the top of the formation is a slate. The Mesnard 
quartzite is the first deposit of the westward transgressing Lower 
Marquette sea. By the time the sea had advanced westward a short 
