OF DENISON UNIVERSITY. 
143 
Fig. 4. (No. 1056.) Section of diabase from large dyke cutting the point next 
west of Eagle river. 
5 - (No. 1018.) Chlorite scales. 
Fig. 5. B. (No. 1018.) pseudomorph of chlorite after mica. 
Fig. 6. Baveno twin of orthoclase from-'granite No. 1059. 
Fig. 7. (No. 1088.) Diabase-aphanite capping the conglomerate near west 
end of Michipicoten island. The conglomerate extends 30 feet above the water’s 
edge and is covered by the aphanitic phase of 1088, which becomes more porphy- 
ritic above. The conglomerate is itself altered to a porphyry near contact. 
I^ig. 8. Twin of augite from dyke (No. iiii.) at west side of Dog river at 
its mouth, a. augite,/". feldspar, m. magnetite, u. uralite. 
Fiq. 9. Conglomerate near Dog river, (No. 1023.) pebbles being 12 inches 
in diameter. From a photograph. 
Fig. 10. Diagram of supposed geological structure of lake Superior, partly 
after Irving. A section through Michipicoten island and and Keweenan point. 
PLATE XIII. 
Fig. I. Section of the porphyry No. 1099a, with a slightly corroded isotrop- 
ous transverse section of quartz. 
hig. 2. No. loSya. Altered mica schist as a boulder in 1096. 
Fig. 3. Pseud-amygdule from 1077, with concentric ferruginous bands. 
Fig. 4. Pseud-amygdule in 1091. 
Fi^. 5. Augite twin in granite No. 1107, near contact. /. feldspar, q. quartz- 
Fig. 6. Highly magnified portion of No. 1019a. Diabase porphyrite at 
Dog river, with grouped crystals of titanic iron. 
Fig. 7. Section of No, 1082a. with concentric pseud-amygdules of chlorite 
in stellate polyhedral aggregates, f. plagioclase. The black is magnetic. 
Fig. 8. Altering crystal of plagioclase in 1083. 
Fig. 9. A. map of region about Michipicoten} river, north shore of lake Su- 
perio.r. B. Section along A B in above map. 
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