194 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
times brownish-red, and again bright-red, irregularly mottled with the 
light-gray kind. 
Briefly summarized, then, the Portage Lake section is as follows: 
UPPER DIVISION OF THE KEWEENAW SERIES. 
Thickness in feet. 
Largely covered, but apparently for the most part red shales and sandstone; 
towards the base there is a considerable thickness (upwards of 200 feet) 
of dark-colored, fine-grained sandstone and black shale, in which the 
usual porphyry detritus is mingled with more or less basic detritus , the 
lowest layers are also conglomeratic; in all about.................... 9,000 
LOWER DIVISION OF THE KEWEENAW SERIES. 
Covered space of some 1,200 feet, in which must be the equivalents of the 
outer trap of the eastern part of Keweenaw Point, corresponding to a 
thickness of abouts... <sn/oscensecte cis eit eee eee eee eet 500 
The Great Conglomerate, including the sandstone and conglomerate at the 
Atlantic mill and conglomerate 22 on the south side of Portage Lake, 
with some intervening exposures; about.......................... ..-- 1,500 
Diabase saa-canescase is oe eee eer Aine Ce i ee ead Sc 66 
Conglomerate 2 riae = cy ier ergede stele rere eee te ate ee ets ea enero 15 
Diabaseand amygdaloid) «25/7 eeseeee sone eee eae ee ener einer 51 
Conglomerate: 20 <= 5. oo aes a eitepeeatcle Be POCO aces AAS OOe 19 
IDE ty ee RRR DEO SaOeuocD Datos coccus.cee eo dias gies Wee eee tne rare este ste eteteatele 100 
Conglomerate 19... 2. Ste te Sa eee rete e oie ana eee tee eee 13 
Diabase. 2.561: < ies oaths bli ee eee ee EAA Jota c eet aen oneoee 94 
Conglomerate 18: 2. :.i0'< Sis ote seqnngee see arses 2G ae See ener ieee 155 
Diabases and amygdaloids ..........-...-...- SBuecne tesa nos Dododocacoce 340 
Conglomerated 7(Hancoeks Wiest) Weenie eater eet eet ere 32 
Diabases and amygdaloids ; including the South Pewabic cupriferous amygda- 
loid at 50:feet below 1:75 . 2 spoons ce ee eee eee eee 550 
Conglomerate 16 (not seen on. south side Portage Lake) SP bodeasroncocéoce 10 
Diabases and amygdaloids; including, at 400 feet above conglomerate 15, the 
Pewabie cupriferous amygdaloid or “lode” so ee worked for cop- 
per on the west side of Portage Lake ........-......-..........---<-. 900 
Conglomerate 15 (Albany and Boston conglomerate on ‘the north side of 
Portage dake) .2cc .s2h.cci4 seat ee eee eee Sopesneapounescocc 33 
Diabases and amygdaloids..... ss spc. gadewie eces pene een ee eee eer 330 
Conglomerate 14 (the Houghton conglomerate of the north shore)...-..... -. 2 
Diabases'and amyedaloids-. ore etek. ee en ee eee eee ete 1, 460 
Conglomerate 12 (north side of Portage Lake) ...-.-... ..-.-....---.--.---. 3 
Diabases and amygdaloids................ a iesajends Sis eS 6 oye Sie terenete sree ererere as 680 
Conglomerate TL... oc 5.2% 2: «cassis sesso elnlet seem ssi shele Sle etela oiatel Te eee eer eee 20 
Diabases'and amygdaloids 32.55%. sass2))- 22s Peete eee eee eee eee 200 
Conglomerate 10 te s.)--s--s eee nage jared eae siete eins OEE EE eee eee 60 
Diabasesiand amyedaloids.- 22. cscs. .scecen canes ee eoeaeee =soncode = doses 460 
Conglomerate 9 (sandstone seam)! 22/5222 F- 22 ge sels eee eee eae ieee 
