200 T. B. Brooks—Rocks observed in the Huronian Sri 
of sandstone—8, 21, 777. Micaceous quartz schist, often con- 
glomeritic—rgo, 50, 51. Quartz conglomerate (see remarks — 
under “Fragmental Rocks”), associated with and constitutin 
a variety of the above—145. Chloritic arenaceous—138, Blue- 
ray, arenaceous, weathering to a brown sandstone — 739, 
Banded magnetite and arenaceous quartz schist—52. Micaceous 
and specular iron—32, 83, 49. Limonitic—26. (The three last 
varieties are also classed under Iron-ore. rocks.) Calcareous. 
(2.) Sthceous Schists, compact, often slaty, generally ferrugi- 
nous, and graduating into siliceous flaggy iron-ores, are abun- 
dant. Poor in iron. Rich in iron (siliceous flag ores) —23, 36, 
68. (See Iron-ore rocks.) 
(3.) Chert. A flinty rock, flaggy to slaty, between siliceous 
schist and jasper, abundant only in the middle of the Black 
River series. Sometimes brecciated—85, 84? Lydianstone— 
very rare. 
(4.) Itacolumyte. 
(5.) Jasper Fock. An impure reddish variety, banded with 
ou ore, is abundant in the Marquette Region—37. Better 
characterized, banded, often ferruginous, jaspers occur with — 
chert in the Black River series. Sometimes brecciated—84, 85? 
(6.) Buhrstone. 
8. Lron-ore Rocks. 
Magnetites, Hematites (usually s ecular), Zimonites, and related 
rruginous rocks are very abundant in the Middle and Lower 
Huronian, especially in the eastern portion of this Huronian 
area, while they are comparatively rare in the same series im 
Canada. At least seven out of the twenty beds of the Marquette 
Region are ferruginous, and four have produced first-class ores. 
The rich specular hematite, which is so far most extensively 
mined, is mostly confined, however, to bed XIII, in which the 
richest magnetites also occur. There is less iron in the Menom 
inee Region, and still less and of lower grade, so far as observ 
in the Black River and Bad River series. ; h 
The magnetites and specular hematites graduate into eac 
other through martite, which is abundant. They are also some 
times interstratified in the same bed, although seldom in juxts 
ition. Nearly the same may be said of the hematites 
imonites, but not of the latter and magnetites, which are nev 
ei igi etites, | 
ores, whatever their origin, were once all magn y es 
. in consid- 
No rocks are embraced below which do not occur in 
erable beds. To include all of them I have found it necessary 
to considerably expand the skeleton given by Professor Dan’ 
