An ecological survey in northern An ecological survey in northern Michigan ecologicalsurvey00adam Year: 1906 R. XLIV W. H. XLIII W R. XLII W. R. W. Fig. 1. Geological map of a portion of the Porcupine Mountains. Mich. 2. Qunrtz-porplijry. 3. Diabase, Diabase-amygdaloid ('Trap'). 4. Sandstone and Conglomerate. .5. Diabase and Diabase-nmygdaiOid ('Trap') 6. Sandstone witlitliin bands of conglomerate. 7. Dark-grey Sandstone and Black Siiale.— (After Irving).

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