By T. B. BROOKS. 
e Sequence of Huronian Strata at several points near Lake Superior, with Hypothesis of Equivalency. 
NORTH OF LAKE HURON, 
CANADA. 
Geology of Canada, 1863. 
Norg._Important beds of iron-ore, pro 
— , occur 
or in Canada, but — stratigraphi- 
ae hen is not known to m 
l. White quartz, chert and limestone. 
k. Yellow chert and limestone. 
i. White quartzyte. 
Greenstone. 
Yellowish chert and limestone. 
i. White quartayte. 
h, Red jasper conglomerate. 
g. Red quartzyte ? 
ee Slate conglomerate with beds of green- 
<. Limestone, so 
ibbed. me beds dolomitic and 
d. Slate conglomerate, with h ‘ 
stratified beds of greenstone. oe 
* 
Greenstone. 
b. << oneal and epidotic 
ting well he srong_ and oh solid, void re- 
Slate conglomerate. 
hably 
near the eastern whore. of 
¢, White ate 
eritic. quartzyte, sometimes conglom- 
2 5, 6, 73, 14. 
ee TRON REGION, 
{ICHIGAN. 
T. B. Brooks. 
LOWER SILURIAN. 
CopPER SERIES (WANTING). 
XIX. Grayish-black mica schist, often 
staurolitic and holding andalusite and gar- 
nets; rarely chloritie schist. 
Quartz in 
hes ache es er ne and Aueubleans seams, 
Cae 
Qua rizyte? 
Probably soft slate. 
XVII. Anthophyllitic? schist, usually mag- 
netic, and containing manganese. 58, 59. 
XVI. Banded ochrey porous quartz 
schist. 57. 
XV. Blackish argillaceous slate, with im- 
perfect cleavage, rarely micaceous, and 
sometimes holding garnets. 56. 
XIV. Gray arenaceous quartzyle, often 
semi-schistose and sometimes micaceous ; 
quartz conglomerate. 50, 51, 145. 
. Pure ete or and ma 
ou 
‘Trap dykes” at 
ington Mine. 36 to 49, 52 to 55, 89. 
Me on 
. Red —— quartz schist, — 
ed with micaceous-i ; quartzose limonitic 
ores. =. 52. 33, rea 38.) 
XI. Dioryt nblende schist, chloritic 
schist, <hlotictoking mica schist ; rarely 
ornb e gneiss. 118, 29, 3 0, 107. 
= Bitiscos pees and imonitis ced 
ores, often aniferous 
chia: piace Shoes e anthophyiiitic ania 
schi ; obseu itic ? 
radon oe schists, ore conchoidal fracture 
24, 25, ms 23.27.41 
Ix. ornblendic ae and related gy 
and ee often micaceous. 22, 88, 
VIII. Ferruginous qguartzose flags; ¢ 
rarely peng ae and Eboes 
slate ; quartzyte, ra 
nyliige? schist. 19, 
Hor spe dic ponte with related 
greenstones? 18 
VI. Ferruginous quartzose schist; clay 
and chloritic slates? 15, 16, a 
V. Quartzyte ovadicatian into sectorins 
with eer beds of dolomitic ma 
bie; novaculyte; rarely chloritic and ae 
ceous schist, ahd dykes of chloritic schist. 
slates, oe ce 
quartzose iron ll-characterized 
| schist is tonitid tn m only at Mar- | 
quette. 77, 116, 7 os "120, 12], 71, 76.) 
NON-CONFORMABLE WITH 
LAURENTIAN. 
agne- 
schist 
d 
MENOMINEE IRON REGION, 
MICH. anp WISC. 
Pumpelly, Brooks, Credner, Wright. 
CopPpER SERIES (WANTING). 
XX. Granite and gneiss. See Nos. 101, 
ne A oype) suite. 
X. Br ownish- black sit schist, some- 
_ hor ~— schist ; 
iss, sieets Grani 
dykes. Nos. 90, 108, 128, 1a; 103, 134. 
or pede te with chloritic, mica- 
laceous schists and slates 
; also hy- 
ous magnesian schists, mostly “chlor eat 
micaceous quar atite se 
rarely hornblende rocks "and qrcniones: 
114, 115, 146, 1 
XV. Gabbro re diabase) in a heavy bed 
with other greenstones and rela; 
schists, also ferruginous (anthophyllitic ?) 
schist and actinolyte schist. 69, 29. 
. Unctuous-feeling hydrous magne- 
- schist ; sericite ; 
ceous iron and in ‘lates 7 capneaeke ; 
ee chloritie greens 
a - Chloro- ~argillaceous slate, chloritic 
tioryte, carbonaceous clay ‘slate, and 
fe’ oath nat snthonkylige schist. 130. 
Sch ema rock and chlorite-mica schist. 
Micaceous clay slate (phyllite) with a 
of quartz; carbonaceous clay slate. 111. 
Whitish dolomitic marbk, ee reer 
of tremolite and wollastonite 
Chiefly 
with dark- 
ing quartzyte ; say “aa ia ochinn. 
ves sent untiag a clay-slate ; 
-gray, weather- 
113, 139, 
Hornblende schist, 
Hydrous magnesian schist and probably 
Trneinous clay slate; perhaps seri 
136, 6 OBS Sa ae 
V. Grayish to ) white crystalline corns 
| marble, w ith quartz or cherty laminz, pre 
— ohies a ribbed ston. with rare 
and hydrous S$ mag- 
naceous coaale mica schist. 
III. an “psp a ot made 
se conglomerate ; 
quartzyte; and perhaps dioryte. 65, 102. 
NON-CONFORMABLE WITH 
LAURENTIAN. 
erin ss 
artzyte, holding mi- 
ACK RIVER SERIES, 
Between “ee Gogebicand Montreal River, 
MICHIGAN, 
Pumpelly and Brooks. 
LOWER SILURIAN. 
NON-CONFORMABLE WITH CopPER SERIES, 
Here believed to 
overlie non- ee pe conceal 
the Upper Huroni: 
act greenstone with green ch erty? 
Compact 
layers. teak red specks of jasper and 
- | erystals of p 
Greenstone; holds grains of glassy quartz | 
and appears chloritie. 
Hematitic and magnetic quartzose flag. 
(Like Marquette flag ores.) 
_ Gray, Aleta and brown, ba 
ious, silice 
hedral aeivha vage. 
Grayish and greenish banded schist, a 
yer sp In 
apparently ‘elsitic ba and again aphanitic. 
[Covered. ] 
Ferruginous, banded (purple and green) 
cherty schist (magnetic ¢). 
Banded ferruginous jasper schist. 
Ferruginous siliceous flags (not magnetic). 
Arenaceous quartzose schist. 
Reddish quartzyte. , 
Hydrous magnesian or argillaceous schist. 
Greenstone. 
Banded cherty Sel 
breccia, more or le’ 
Compact hard 
ist and schistose cherty 
sferruginous. 84, 85. 
ensi 
Greenston 
Band serra Nous, 
ed siliceous 
strongly ead 
Greens 
Banded ferruginus slate. 
Massive greenstone apparently chloritic. 
Banded ferruginous jasper schist. 
nen ite 
banded, Jerrug 
slate, with strong rhombo- | 
-| qua 
BAD RIVER AND PENOKIE GAP, 
WISCONSIN. 
T. B. Brooks. 
LOWER SILURIAN. 
NON-CONFORMABLE WITH COPPER SERIES, 
Believed to i queue with 
e followi 
Red, gray, coarse and fine vee granitic 
rock, rarely schistose 
Green r hornblende rock, appar- 
ently chloritie, isiawwtak soft, but ton gh). 
[Covered about 4 mile.] 
Clay slate? 
a amphibolic erraae! flags, and — 
se magnetic ore. 148, Heavy bed 
pest crest of ridge. 
Black clay slate without oblique cleav- 
age. 
y quartz schist, vga with occa- 
Pha Meireets of magne 
schist, | 
Grayish and reddish quartzose schist. 
Greenstone (thin bed). : 
Soft, light gray-green slate, probably — 
chloro-argillaceous. 
Gray quartzose schist faintly banded. 
Gray to white, massive quartzyte. Thin 
bed. 
Caleareous rock ? 
mphibole schist and perhaps horn- 
ea gneiss in heavy beds. 
[Covered.] 
BELIEVED TO BE NoN-CONFORMABLE with 
LAURENTIAN. 
S eae and XIX. of the the Marquette and Menominee 
tho Wear series is provisional; and 
gs Ree ee 
— 
even this much is not asserted in the 
is regarded as established, and the 
ce a Uscedion. "hte tartsea cal? 
atl 
typical rocks from certa 
beds are believed to he nearly as arranged. The equivalency in ndicated for 
n beds, 
named in the accompanying Classified _ 
